docs: update CLAUDE.md with additional utilities and supported formats

- Implement functionality to create, update, delete, and view relationships between tables.
- Introduce new UI screens for managing relationships, including forms for adding and editing relationships.
- Enhance table editor with navigation to relationship management.
- Ensure relationships are displayed in a structured table format for better usability.

CLAUDE.md

@@ -4,7 +4,11 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Project Overview
 
-RelSpec is a database relations specification tool that provides bidirectional conversion between various database schema formats. It reads database schemas from multiple sources (live databases, DBML, DCTX, DrawDB, etc.) and writes them to various formats (GORM, Bun, JSON, YAML, SQL, etc.).
+RelSpec is a database relations specification tool that provides bidirectional conversion between various database schema formats. It reads database schemas from multiple sources and writes them to various formats.
+
+**Supported Readers:** Bun, DBML, DCTX, DrawDB, Drizzle, GORM, GraphQL, JSON, PostgreSQL, Prisma, SQL Directory, SQLite, TypeORM, YAML
+
+**Supported Writers:** Bun, DBML, DCTX, DrawDB, Drizzle, GORM, GraphQL, JSON, PostgreSQL, Prisma, SQL Exec, SQLite, Template, TypeORM, YAML
 
 ## Build Commands
 
@@ -50,8 +54,9 @@ Database
 ```
 
 **Important patterns:**
-- Each format (dbml, dctx, drawdb, etc.) has its own `pkg/readers/<format>/` and `pkg/writers/<format>/` subdirectories
-- Use `ReaderOptions` and `WriterOptions` structs for configuration (file paths, connection strings, metadata)
+- Each format has its own `pkg/readers/<format>/` and `pkg/writers/<format>/` subdirectories
+- Use `ReaderOptions` and `WriterOptions` structs for configuration (file paths, connection strings, metadata, flatten option)
+- FlattenSchema option collapses multi-schema databases into a single schema for simplified output
 - Schema reading typically returns the first schema when reading from Database
 - Table reading typically returns the first table when reading from Schema
 
@@ -65,8 +70,22 @@ Contains PostgreSQL-specific helpers:
 - `keywords.go`: SQL reserved keywords validation
 - `datatypes.go`: PostgreSQL data type mappings and conversions
 
+### Additional Utilities
+
+- **pkg/diff/**: Schema difference detection and comparison
+- **pkg/inspector/**: Schema inspection and analysis tools
+- **pkg/merge/**: Schema merging capabilities
+- **pkg/reflectutil/**: Reflection utilities for dynamic type handling
+- **pkg/ui/**: Terminal UI components for interactive schema editing
+- **pkg/commontypes/**: Shared type definitions
+
 ## Development Patterns
 
+- Each reader/writer is self-contained in its own subdirectory
+- Options structs control behavior (file paths, connection strings, flatten schema, etc.)
+- Live database connections supported for PostgreSQL and SQLite
+- Template writer allows custom output formats
+
 ## Testing
 
 - Test files should be in the same package as the code they test
@@ -77,5 +96,6 @@ Contains PostgreSQL-specific helpers:
 ## Module Information
 
 - Module path: `git.warky.dev/wdevs/relspecgo`
-- Go version: 1.25.5
-- Uses Cobra for CLI, Viper for configuration
+- Go version: 1.24.0
+- Uses Cobra for CLI
+- Key dependencies: pgx/v5 (PostgreSQL), modernc.org/sqlite (SQLite), tview (TUI), Bun ORM

GODOC.md

@@ -0,0 +1,196 @@
+# RelSpec API Documentation (godoc)
+
+This document explains how to access and use the RelSpec API documentation.
+
+## Viewing Documentation Locally
+
+### Using `go doc` Command Line
+
+View package documentation:
+```bash
+# Main package overview
+go doc
+
+# Specific package
+go doc ./pkg/models
+go doc ./pkg/readers
+go doc ./pkg/writers
+go doc ./pkg/ui
+
+# Specific type or function
+go doc ./pkg/models Database
+go doc ./pkg/readers Reader
+go doc ./pkg/writers Writer
+```
+
+View all documentation for a package:
+```bash
+go doc -all ./pkg/models
+go doc -all ./pkg/readers
+go doc -all ./pkg/writers
+```
+
+### Using `godoc` Web Server
+
+**Quick Start (Recommended):**
+```bash
+make godoc
+```
+
+This will automatically install godoc if needed and start the server on port 6060.
+
+**Manual Installation:**
+```bash
+go install golang.org/x/tools/cmd/godoc@latest
+godoc -http=:6060
+```
+
+Then open your browser to:
+```
+http://localhost:6060/pkg/git.warky.dev/wdevs/relspecgo/
+```
+
+## Package Documentation
+
+### Core Packages
+
+- **`pkg/models`** - Core data structures (Database, Schema, Table, Column, etc.)
+- **`pkg/readers`** - Input format readers (dbml, pgsql, gorm, prisma, etc.)
+- **`pkg/writers`** - Output format writers (dbml, pgsql, gorm, prisma, etc.)
+
+### Utility Packages
+
+- **`pkg/diff`** - Schema comparison and difference detection
+- **`pkg/merge`** - Schema merging utilities
+- **`pkg/transform`** - Validation and normalization
+- **`pkg/ui`** - Interactive terminal UI for schema editing
+
+### Support Packages
+
+- **`pkg/pgsql`** - PostgreSQL-specific utilities
+- **`pkg/inspector`** - Database introspection capabilities
+- **`pkg/reflectutil`** - Reflection utilities for Go code analysis
+- **`pkg/commontypes`** - Shared type definitions
+
+### Reader Implementations
+
+Each reader is in its own subpackage under `pkg/readers/`:
+
+- `pkg/readers/dbml` - DBML format reader
+- `pkg/readers/dctx` - DCTX format reader
+- `pkg/readers/drawdb` - DrawDB JSON reader
+- `pkg/readers/graphql` - GraphQL schema reader
+- `pkg/readers/json` - JSON schema reader
+- `pkg/readers/yaml` - YAML schema reader
+- `pkg/readers/gorm` - Go GORM models reader
+- `pkg/readers/bun` - Go Bun models reader
+- `pkg/readers/drizzle` - TypeScript Drizzle ORM reader
+- `pkg/readers/prisma` - Prisma schema reader
+- `pkg/readers/typeorm` - TypeScript TypeORM reader
+- `pkg/readers/pgsql` - PostgreSQL database reader
+- `pkg/readers/sqlite` - SQLite database reader
+
+### Writer Implementations
+
+Each writer is in its own subpackage under `pkg/writers/`:
+
+- `pkg/writers/dbml` - DBML format writer
+- `pkg/writers/dctx` - DCTX format writer
+- `pkg/writers/drawdb` - DrawDB JSON writer
+- `pkg/writers/graphql` - GraphQL schema writer
+- `pkg/writers/json` - JSON schema writer
+- `pkg/writers/yaml` - YAML schema writer
+- `pkg/writers/gorm` - Go GORM models writer
+- `pkg/writers/bun` - Go Bun models writer
+- `pkg/writers/drizzle` - TypeScript Drizzle ORM writer
+- `pkg/writers/prisma` - Prisma schema writer
+- `pkg/writers/typeorm` - TypeScript TypeORM writer
+- `pkg/writers/pgsql` - PostgreSQL SQL writer
+- `pkg/writers/sqlite` - SQLite SQL writer
+
+## Usage Examples
+
+### Reading a Schema
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+)
+
+reader := dbml.NewReader(&readers.ReaderOptions{
+    FilePath: "schema.dbml",
+})
+db, err := reader.ReadDatabase()
+```
+
+### Writing a Schema
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/gorm"
+)
+
+writer := gorm.NewWriter(&writers.WriterOptions{
+    OutputPath:  "./models",
+    PackageName: "models",
+})
+err := writer.WriteDatabase(db)
+```
+
+### Comparing Schemas
+
+```go
+import "git.warky.dev/wdevs/relspecgo/pkg/diff"
+
+result := diff.CompareDatabases(sourceDB, targetDB)
+err := diff.FormatDiff(result, diff.OutputFormatText, os.Stdout)
+```
+
+### Merging Schemas
+
+```go
+import "git.warky.dev/wdevs/relspecgo/pkg/merge"
+
+result := merge.MergeDatabases(targetDB, sourceDB, nil)
+fmt.Printf("Added %d tables\n", result.TablesAdded)
+```
+
+## Documentation Standards
+
+All public APIs follow Go documentation conventions:
+
+- Package documentation in `doc.go` files
+- Type, function, and method comments start with the item name
+- Examples where applicable
+- Clear description of parameters and return values
+- Usage notes and caveats where relevant
+
+## Generating Documentation
+
+To regenerate documentation after code changes:
+
+```bash
+# Verify documentation builds correctly
+go doc -all ./pkg/... > /dev/null
+
+# Check for undocumented exports
+go vet ./...
+```
+
+## Contributing Documentation
+
+When adding new packages or exported items:
+
+1. Add package documentation in a `doc.go` file
+2. Document all exported types, functions, and methods
+3. Include usage examples for complex APIs
+4. Follow Go documentation style guide
+5. Verify with `go doc` before committing
+
+## References
+
+- [Go Documentation Guide](https://go.dev/doc/comment)
+- [Effective Go - Commentary](https://go.dev/doc/effective_go#commentary)
+- [godoc Documentation](https://pkg.go.dev/golang.org/x/tools/cmd/godoc)

Makefile

@@ -1,4 +1,4 @@
-.PHONY: all build test test-unit test-integration lint coverage clean install help docker-up docker-down docker-test docker-test-integration start stop release release-version
+.PHONY: all build test test-unit test-integration lint coverage clean install help docker-up docker-down docker-test docker-test-integration start stop release release-version godoc
 
 # Binary name
 BINARY_NAME=relspec
@@ -101,6 +101,29 @@ deps: ## Download dependencies
 	$(GOMOD) tidy
 	@echo "Dependencies updated"
 
+godoc: ## Start godoc server on http://localhost:6060
+	@echo "Starting godoc server..."
+	@GOBIN=$$(go env GOPATH)/bin; \
+	if command -v godoc > /dev/null 2>&1; then \
+		echo "godoc server running on http://localhost:6060"; \
+		echo "View documentation at: http://localhost:6060/pkg/git.warky.dev/wdevs/relspecgo/"; \
+		echo "Press Ctrl+C to stop"; \
+		godoc -http=:6060; \
+	elif [ -f "$$GOBIN/godoc" ]; then \
+		echo "godoc server running on http://localhost:6060"; \
+		echo "View documentation at: http://localhost:6060/pkg/git.warky.dev/wdevs/relspecgo/"; \
+		echo "Press Ctrl+C to stop"; \
+		$$GOBIN/godoc -http=:6060; \
+	else \
+		echo "godoc not installed. Installing..."; \
+		go install golang.org/x/tools/cmd/godoc@latest; \
+		echo "godoc installed. Starting server..."; \
+		echo "godoc server running on http://localhost:6060"; \
+		echo "View documentation at: http://localhost:6060/pkg/git.warky.dev/wdevs/relspecgo/"; \
+		echo "Press Ctrl+C to stop"; \
+		$$GOBIN/godoc -http=:6060; \
+	fi
+
 start: docker-up ## Alias for docker-up (start PostgreSQL test database)
 
 stop: docker-down ## Alias for docker-down (stop PostgreSQL test database)

README.md

@@ -37,6 +37,7 @@ RelSpec can read database schemas from multiple sources:
 
 #### Database Inspection
 - [PostgreSQL](pkg/readers/pgsql/README.md) - Direct PostgreSQL database introspection
+- [SQLite](pkg/readers/sqlite/README.md) - Direct SQLite database introspection
 
 #### Schema Formats
 - [DBML](pkg/readers/dbml/README.md) - Database Markup Language (dbdiagram.io)
@@ -59,6 +60,7 @@ RelSpec can write database schemas to multiple formats:
 
 #### Database DDL
 - [PostgreSQL](pkg/writers/pgsql/README.md) - PostgreSQL DDL (CREATE TABLE, etc.)
+- [SQLite](pkg/writers/sqlite/README.md) - SQLite DDL with automatic schema flattening
 
 #### Schema Formats
 - [DBML](pkg/writers/dbml/README.md) - Database Markup Language
@@ -185,6 +187,10 @@ relspec convert --from pgsql --from-conn "postgres://..." \
 # Convert DBML to PostgreSQL SQL
 relspec convert --from dbml --from-path schema.dbml \
                 --to pgsql --to-path schema.sql
+
+# Convert PostgreSQL database to SQLite (with automatic schema flattening)
+relspec convert --from pgsql --from-conn "postgres://..." \
+                --to sqlite --to-path sqlite_schema.sql
 ```
 
 ### Schema Validation

TODO.md

@@ -1,43 +1,44 @@
 # RelSpec - TODO List
 
-
 ## Input Readers / Writers
 
 - [✔️] **Database Inspector**
-  - [✔️] PostgreSQL driver
+  - [✔️] PostgreSQL driver (reader + writer)
   - [ ] MySQL driver
-  - [ ] SQLite driver
+  - [✔️] SQLite driver (reader + writer with automatic schema flattening)
   - [ ] MSSQL driver
   - [✔️] Foreign key detection
   - [✔️] Index extraction
-  - [*] .sql file generation with sequence and priority
+  - [✔️] .sql file generation (PostgreSQL, SQLite)
 - [✔️] .dbml: Database Markup Language (DBML) for textual schema representation.
 - [✔️] Prisma schema support (PSL format) .prisma
-- [✔️] Drizzle ORM support .ts (TypeScript / JavaScript)  (Mr. Edd wanted to move from Prisma to Drizzle. If you are bugs, you are welcome to do pull requests or issues)
-- [☠️] Entity Framework (.NET) model .edmx  (Fuck no, EDMX files were bloated, verbose XML nightmares—hard to merge, error-prone, and a pain in teams. Microsoft wisely ditched them in EF Core for code-first. Classic overkill from old MS era.)
+- [✔️] Drizzle ORM support .ts (TypeScript / JavaScript) (Mr. Edd wanted to move from Prisma to Drizzle. If you are bugs, you are welcome to do pull requests or issues)
+- [☠️] Entity Framework (.NET) model .edmx (Fuck no, EDMX files were bloated, verbose XML nightmares—hard to merge, error-prone, and a pain in teams. Microsoft wisely ditched them in EF Core for code-first. Classic overkill from old MS era.)
 - [✔️] TypeORM support
-- [] .hbm.xml / schema.xml: Hibernate/Propel mappings (Java/PHP)  (💲 Someone can do this, not me)
+- [] .hbm.xml / schema.xml: Hibernate/Propel mappings (Java/PHP) (💲 Someone can do this, not me)
 - [ ] Django models.py (Python classes), Sequelize migrations (JS) (💲 Someone can do this, not me)
 - [] .avsc: Avro schema (JSON format for data serialization) (💲 Someone can do this, not me)
 - [✔️] GraphQL schema generation
 
+## UI
 
-## UI 
 - [✔️] Basic UI (I went with tview)
 - [✔️] Save / Load Database
 - [✔️] Schemas / Domains / Tables
-- [  ] Add Relations
-- [  ] Add Indexes
-- [  ] Add Views
-- [  ] Add Sequences
-- [  ] Add Scripts
-- [  ] Domain / Table Assignment
+- [✔️] Add Relations
+- [ ] Add Indexes
+- [ ] Add Views
+- [ ] Add Sequences
+- [ ] Add Scripts
+- [ ] Domain / Table Assignment
 
 ## Documentation
-- [ ] API documentation (godoc)
+
+- [✔️] API documentation (godoc)
 - [ ] Usage examples for each format combination
 
 ## Advanced Features
+
 - [ ] Dry-run mode for validation
 - [x] Diff tool for comparing specifications
 - [ ] Migration script generation
@@ -46,12 +47,13 @@
 - [ ] Watch mode for auto-regeneration
 
 ## Future Considerations
+
 - [ ] Web UI for visual editing
 - [ ] REST API server mode
 - [ ] Support for NoSQL databases
 
-
 ## Performance
+
 - [ ] Concurrent processing for multiple tables
 - [ ] Streaming for large databases
 - [ ] Memory optimization

cmd/relspec/convert.go

@@ -20,6 +20,7 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/json"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/prisma"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/typeorm"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
@@ -33,18 +34,20 @@ import (
 	wjson "git.warky.dev/wdevs/relspecgo/pkg/writers/json"
 	wpgsql "git.warky.dev/wdevs/relspecgo/pkg/writers/pgsql"
 	wprisma "git.warky.dev/wdevs/relspecgo/pkg/writers/prisma"
+	wsqlite "git.warky.dev/wdevs/relspecgo/pkg/writers/sqlite"
 	wtypeorm "git.warky.dev/wdevs/relspecgo/pkg/writers/typeorm"
 	wyaml "git.warky.dev/wdevs/relspecgo/pkg/writers/yaml"
 )
 
 var (
-	convertSourceType   string
-	convertSourcePath   string
-	convertSourceConn   string
-	convertTargetType   string
-	convertTargetPath   string
-	convertPackageName  string
-	convertSchemaFilter string
+	convertSourceType    string
+	convertSourcePath    string
+	convertSourceConn    string
+	convertTargetType    string
+	convertTargetPath    string
+	convertPackageName   string
+	convertSchemaFilter  string
+	convertFlattenSchema bool
 )
 
 var convertCmd = &cobra.Command{
@@ -69,6 +72,7 @@ Input formats:
   - prisma: Prisma schema files (.prisma)
   - typeorm: TypeORM entity files (TypeScript)
   - pgsql: PostgreSQL database (live connection)
+  - sqlite: SQLite database file
 
 Output formats:
   - dbml: DBML schema files
@@ -83,13 +87,20 @@ Output formats:
   - prisma: Prisma schema files (.prisma)
   - typeorm: TypeORM entity files (TypeScript)
   - pgsql: PostgreSQL SQL schema
+  - sqlite: SQLite SQL schema (with automatic schema flattening)
 
-PostgreSQL Connection String Examples:
-  postgres://username:password@localhost:5432/database_name
-  postgres://username:password@localhost/database_name
-  postgresql://user:pass@host:5432/dbname?sslmode=disable
-  postgresql://user:pass@host/dbname?sslmode=require
-  host=localhost port=5432 user=username password=pass dbname=mydb sslmode=disable
+Connection String Examples:
+  PostgreSQL:
+    postgres://username:password@localhost:5432/database_name
+    postgres://username:password@localhost/database_name
+    postgresql://user:pass@host:5432/dbname?sslmode=disable
+    postgresql://user:pass@host/dbname?sslmode=require
+    host=localhost port=5432 user=username password=pass dbname=mydb sslmode=disable
+
+  SQLite:
+    /path/to/database.db
+    ./relative/path/database.sqlite
+    database.db
 
 
 Examples:
@@ -135,19 +146,28 @@ Examples:
 
   # Convert Bun models directory to JSON
   relspec convert --from bun --from-path ./models \
-                  --to json --to-path schema.json`,
+                  --to json --to-path schema.json
+
+  # Convert SQLite database to JSON
+  relspec convert --from sqlite --from-path database.db \
+                  --to json --to-path schema.json
+
+  # Convert SQLite to PostgreSQL SQL
+  relspec convert --from sqlite --from-path database.db \
+                  --to pgsql --to-path schema.sql`,
 	RunE: runConvert,
 }
 
 func init() {
-	convertCmd.Flags().StringVar(&convertSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
+	convertCmd.Flags().StringVar(&convertSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, sqlite)")
 	convertCmd.Flags().StringVar(&convertSourcePath, "from-path", "", "Source file path (for file-based formats)")
-	convertCmd.Flags().StringVar(&convertSourceConn, "from-conn", "", "Source connection string (for database formats)")
+	convertCmd.Flags().StringVar(&convertSourceConn, "from-conn", "", "Source connection string (for pgsql) or file path (for sqlite)")
 
 	convertCmd.Flags().StringVar(&convertTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
 	convertCmd.Flags().StringVar(&convertTargetPath, "to-path", "", "Target output path (file or directory)")
 	convertCmd.Flags().StringVar(&convertPackageName, "package", "", "Package name (for code generation formats like gorm/bun)")
 	convertCmd.Flags().StringVar(&convertSchemaFilter, "schema", "", "Filter to a specific schema by name (required for formats like dctx that only support single schemas)")
+	convertCmd.Flags().BoolVar(&convertFlattenSchema, "flatten-schema", false, "Flatten schema.table names to schema_table (useful for databases like SQLite that do not support schemas)")
 
 	err := convertCmd.MarkFlagRequired("from")
 	if err != nil {
@@ -202,7 +222,7 @@ func runConvert(cmd *cobra.Command, args []string) error {
 		fmt.Fprintf(os.Stderr, "      Schema: %s\n", convertSchemaFilter)
 	}
 
-	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter); err != nil {
+	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter, convertFlattenSchema); err != nil {
 		return fmt.Errorf("failed to write target: %w", err)
 	}
 
@@ -289,6 +309,17 @@ func readDatabaseForConvert(dbType, filePath, connString string) (*models.Databa
 		}
 		reader = graphql.NewReader(&readers.ReaderOptions{FilePath: filePath})
 
+	case "sqlite", "sqlite3":
+		// SQLite can use either file path or connection string
+		dbPath := filePath
+		if dbPath == "" {
+			dbPath = connString
+		}
+		if dbPath == "" {
+			return nil, fmt.Errorf("file path or connection string is required for SQLite format")
+		}
+		reader = sqlite.NewReader(&readers.ReaderOptions{FilePath: dbPath})
+
 	default:
 		return nil, fmt.Errorf("unsupported source format: %s", dbType)
 	}
@@ -301,12 +332,13 @@ func readDatabaseForConvert(dbType, filePath, connString string) (*models.Databa
 	return db, nil
 }
 
-func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string) error {
+func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool) error {
 	var writer writers.Writer
 
 	writerOpts := &writers.WriterOptions{
-		OutputPath:  outputPath,
-		PackageName: packageName,
+		OutputPath:    outputPath,
+		PackageName:   packageName,
+		FlattenSchema: flattenSchema,
 	}
 
 	switch strings.ToLower(dbType) {
@@ -343,6 +375,9 @@ func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaF
 	case "pgsql", "postgres", "postgresql", "sql":
 		writer = wpgsql.NewWriter(writerOpts)
 
+	case "sqlite", "sqlite3":
+		writer = wsqlite.NewWriter(writerOpts)
+
 	case "prisma":
 		writer = wprisma.NewWriter(writerOpts)
 

cmd/relspec/diff.go

@@ -16,6 +16,7 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/drawdb"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/json"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
 )
 
@@ -254,6 +255,17 @@ func readDatabase(dbType, filePath, connString, label string) (*models.Database,
 		}
 		reader = pgsql.NewReader(&readers.ReaderOptions{ConnectionString: connString})
 
+	case "sqlite", "sqlite3":
+		// SQLite can use either file path or connection string
+		dbPath := filePath
+		if dbPath == "" {
+			dbPath = connString
+		}
+		if dbPath == "" {
+			return nil, fmt.Errorf("%s: file path or connection string is required for SQLite format", label)
+		}
+		reader = sqlite.NewReader(&readers.ReaderOptions{FilePath: dbPath})
+
 	default:
 		return nil, fmt.Errorf("%s: unsupported database format: %s", label, dbType)
 	}

cmd/relspec/edit.go

@@ -19,6 +19,7 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/json"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/prisma"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/typeorm"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
 	"git.warky.dev/wdevs/relspecgo/pkg/ui"
@@ -33,6 +34,7 @@ import (
 	wjson "git.warky.dev/wdevs/relspecgo/pkg/writers/json"
 	wpgsql "git.warky.dev/wdevs/relspecgo/pkg/writers/pgsql"
 	wprisma "git.warky.dev/wdevs/relspecgo/pkg/writers/prisma"
+	wsqlite "git.warky.dev/wdevs/relspecgo/pkg/writers/sqlite"
 	wtypeorm "git.warky.dev/wdevs/relspecgo/pkg/writers/typeorm"
 	wyaml "git.warky.dev/wdevs/relspecgo/pkg/writers/yaml"
 )
@@ -73,6 +75,7 @@ Supports reading from and writing to all supported formats:
     - prisma: Prisma schema files (.prisma)
     - typeorm: TypeORM entity files (TypeScript)
     - pgsql: PostgreSQL database (live connection)
+    - sqlite: SQLite database file
 
   Output formats:
     - dbml: DBML schema files
@@ -87,13 +90,19 @@ Supports reading from and writing to all supported formats:
     - prisma: Prisma schema files (.prisma)
     - typeorm: TypeORM entity files (TypeScript)
     - pgsql: PostgreSQL SQL schema
+    - sqlite: SQLite SQL schema (with automatic schema flattening)
 
-PostgreSQL Connection String Examples:
-  postgres://username:password@localhost:5432/database_name
-  postgres://username:password@localhost/database_name
-  postgresql://user:pass@host:5432/dbname?sslmode=disable
-  postgresql://user:pass@host/dbname?sslmode=require
-  host=localhost port=5432 user=username password=pass dbname=mydb sslmode=disable
+Connection String Examples:
+  PostgreSQL:
+    postgres://username:password@localhost:5432/database_name
+    postgres://username:password@localhost/database_name
+    postgresql://user:pass@host:5432/dbname?sslmode=disable
+    postgresql://user:pass@host/dbname?sslmode=require
+    host=localhost port=5432 user=username password=pass dbname=mydb sslmode=disable
+  SQLite:
+    /path/to/database.db
+    ./relative/path/database.sqlite
+    database.db
 
 Examples:
   # Edit a DBML schema file
@@ -107,15 +116,21 @@ Examples:
   relspec edit --from json --from-path db.json --to gorm --to-path models/
 
   # Edit GORM models in place
-  relspec edit --from gorm --from-path ./models --to gorm --to-path ./models`,
+  relspec edit --from gorm --from-path ./models --to gorm --to-path ./models
+
+  # Edit SQLite database
+  relspec edit --from sqlite --from-path database.db --to sqlite --to-path database.db
+
+  # Convert SQLite to DBML
+  relspec edit --from sqlite --from-path database.db --to dbml --to-path schema.dbml`,
 	RunE: runEdit,
 }
 
 func init() {
-	editCmd.Flags().StringVar(&editSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
+	editCmd.Flags().StringVar(&editSourceType, "from", "", "Source format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, sqlite)")
 	editCmd.Flags().StringVar(&editSourcePath, "from-path", "", "Source file path (for file-based formats)")
-	editCmd.Flags().StringVar(&editSourceConn, "from-conn", "", "Source connection string (for database formats)")
-	editCmd.Flags().StringVar(&editTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql)")
+	editCmd.Flags().StringVar(&editSourceConn, "from-conn", "", "Source connection string (for pgsql) or file path (for sqlite)")
+	editCmd.Flags().StringVar(&editTargetType, "to", "", "Target format (dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql, sqlite)")
 	editCmd.Flags().StringVar(&editTargetPath, "to-path", "", "Target file path (for file-based formats)")
 	editCmd.Flags().StringVar(&editSchemaFilter, "schema", "", "Filter to a specific schema by name")
 
@@ -281,6 +296,16 @@ func readDatabaseForEdit(dbType, filePath, connString, label string) (*models.Da
 			return nil, fmt.Errorf("%s: connection string is required for PostgreSQL format", label)
 		}
 		reader = pgsql.NewReader(&readers.ReaderOptions{ConnectionString: connString})
+	case "sqlite", "sqlite3":
+		// SQLite can use either file path or connection string
+		dbPath := filePath
+		if dbPath == "" {
+			dbPath = connString
+		}
+		if dbPath == "" {
+			return nil, fmt.Errorf("%s: file path or connection string is required for SQLite format", label)
+		}
+		reader = sqlite.NewReader(&readers.ReaderOptions{FilePath: dbPath})
 	default:
 		return nil, fmt.Errorf("%s: unsupported format: %s", label, dbType)
 	}
@@ -319,6 +344,8 @@ func writeDatabaseForEdit(dbType, filePath, connString string, db *models.Databa
 		writer = wprisma.NewWriter(&writers.WriterOptions{OutputPath: filePath})
 	case "typeorm":
 		writer = wtypeorm.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+	case "sqlite", "sqlite3":
+		writer = wsqlite.NewWriter(&writers.WriterOptions{OutputPath: filePath})
 	case "pgsql":
 		writer = wpgsql.NewWriter(&writers.WriterOptions{OutputPath: filePath})
 	default:

cmd/relspec/inspect.go

@@ -20,6 +20,7 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/json"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/prisma"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/typeorm"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
 )
@@ -288,6 +289,17 @@ func readDatabaseForInspect(dbType, filePath, connString string) (*models.Databa
 		}
 		reader = pgsql.NewReader(&readers.ReaderOptions{ConnectionString: connString})
 
+	case "sqlite", "sqlite3":
+		// SQLite can use either file path or connection string
+		dbPath := filePath
+		if dbPath == "" {
+			dbPath = connString
+		}
+		if dbPath == "" {
+			return nil, fmt.Errorf("file path or connection string is required for SQLite format")
+		}
+		reader = sqlite.NewReader(&readers.ReaderOptions{FilePath: dbPath})
+
 	default:
 		return nil, fmt.Errorf("unsupported database type: %s", dbType)
 	}

cmd/relspec/merge.go

@@ -21,6 +21,7 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/json"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/prisma"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/typeorm"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
@@ -34,6 +35,7 @@ import (
 	wjson "git.warky.dev/wdevs/relspecgo/pkg/writers/json"
 	wpgsql "git.warky.dev/wdevs/relspecgo/pkg/writers/pgsql"
 	wprisma "git.warky.dev/wdevs/relspecgo/pkg/writers/prisma"
+	wsqlite "git.warky.dev/wdevs/relspecgo/pkg/writers/sqlite"
 	wtypeorm "git.warky.dev/wdevs/relspecgo/pkg/writers/typeorm"
 	wyaml "git.warky.dev/wdevs/relspecgo/pkg/writers/yaml"
 )
@@ -56,6 +58,7 @@ var (
 	mergeSkipTables    string // Comma-separated table names to skip
 	mergeVerbose       bool
 	mergeReportPath    string // Path to write merge report
+	mergeFlattenSchema bool
 )
 
 var mergeCmd = &cobra.Command{
@@ -123,6 +126,7 @@ func init() {
 	mergeCmd.Flags().StringVar(&mergeSkipTables, "skip-tables", "", "Comma-separated list of table names to skip during merge")
 	mergeCmd.Flags().BoolVar(&mergeVerbose, "verbose", false, "Show verbose output")
 	mergeCmd.Flags().StringVar(&mergeReportPath, "merge-report", "", "Path to write merge report (JSON format)")
+	mergeCmd.Flags().BoolVar(&mergeFlattenSchema, "flatten-schema", false, "Flatten schema.table names to schema_table (useful for databases like SQLite that do not support schemas)")
 }
 
 func runMerge(cmd *cobra.Command, args []string) error {
@@ -237,7 +241,7 @@ func runMerge(cmd *cobra.Command, args []string) error {
 		fmt.Fprintf(os.Stderr, "      Path:   %s\n", mergeOutputPath)
 	}
 
-	err = writeDatabaseForMerge(mergeOutputType, mergeOutputPath, mergeOutputConn, targetDB, "Output")
+	err = writeDatabaseForMerge(mergeOutputType, mergeOutputPath, mergeOutputConn, targetDB, "Output", mergeFlattenSchema)
 	if err != nil {
 		return fmt.Errorf("failed to write output: %w", err)
 	}
@@ -312,6 +316,16 @@ func readDatabaseForMerge(dbType, filePath, connString, label string) (*models.D
 			return nil, fmt.Errorf("%s: connection string is required for PostgreSQL format", label)
 		}
 		reader = pgsql.NewReader(&readers.ReaderOptions{ConnectionString: connString})
+	case "sqlite", "sqlite3":
+		// SQLite can use either file path or connection string
+		dbPath := filePath
+		if dbPath == "" {
+			dbPath = connString
+		}
+		if dbPath == "" {
+			return nil, fmt.Errorf("%s: file path or connection string is required for SQLite format", label)
+		}
+		reader = sqlite.NewReader(&readers.ReaderOptions{FilePath: dbPath})
 	default:
 		return nil, fmt.Errorf("%s: unsupported format '%s'", label, dbType)
 	}
@@ -324,7 +338,7 @@ func readDatabaseForMerge(dbType, filePath, connString, label string) (*models.D
 	return db, nil
 }
 
-func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Database, label string) error {
+func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Database, label string, flattenSchema bool) error {
 	var writer writers.Writer
 
 	switch strings.ToLower(dbType) {
@@ -332,59 +346,61 @@ func writeDatabaseForMerge(dbType, filePath, connString string, db *models.Datab
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DBML format", label)
 		}
-		writer = wdbml.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdbml.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "dctx":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DCTX format", label)
 		}
-		writer = wdctx.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdctx.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "drawdb":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for DrawDB format", label)
 		}
-		writer = wdrawdb.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdrawdb.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "graphql":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for GraphQL format", label)
 		}
-		writer = wgraphql.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wgraphql.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "json":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for JSON format", label)
 		}
-		writer = wjson.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wjson.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "yaml":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for YAML format", label)
 		}
-		writer = wyaml.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wyaml.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "gorm":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for GORM format", label)
 		}
-		writer = wgorm.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wgorm.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "bun":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Bun format", label)
 		}
-		writer = wbun.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wbun.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "drizzle":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Drizzle format", label)
 		}
-		writer = wdrizzle.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wdrizzle.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "prisma":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for Prisma format", label)
 		}
-		writer = wprisma.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wprisma.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "typeorm":
 		if filePath == "" {
 			return fmt.Errorf("%s: file path is required for TypeORM format", label)
 		}
-		writer = wtypeorm.NewWriter(&writers.WriterOptions{OutputPath: filePath})
+		writer = wtypeorm.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
+	case "sqlite", "sqlite3":
+		writer = wsqlite.NewWriter(&writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema})
 	case "pgsql":
-		writerOpts := &writers.WriterOptions{OutputPath: filePath}
+		writerOpts := &writers.WriterOptions{OutputPath: filePath, FlattenSchema: flattenSchema}
 		if connString != "" {
 			writerOpts.Metadata = map[string]interface{}{
 				"connection_string": connString,

cmd/relspec/scripts.go

@@ -14,10 +14,11 @@ import (
 )
 
 var (
-	scriptsDir        string
-	scriptsConn       string
-	scriptsSchemaName string
-	scriptsDBName     string
+	scriptsDir          string
+	scriptsConn         string
+	scriptsSchemaName   string
+	scriptsDBName       string
+	scriptsIgnoreErrors bool
 )
 
 var scriptsCmd = &cobra.Command{
@@ -62,7 +63,7 @@ var scriptsExecuteCmd = &cobra.Command{
 	Long: `Execute SQL scripts from a directory against a PostgreSQL database.
 
 Scripts are executed in order: Priority (ascending), Sequence (ascending), Name (alphabetical).
-Execution stops immediately on the first error.
+By default, execution stops immediately on the first error. Use --ignore-errors to continue execution.
 
 The directory is scanned recursively for all subdirectories and files matching the patterns:
   {priority}_{sequence}_{name}.sql or .pgsql (underscore format)
@@ -86,7 +87,12 @@ Examples:
 
   # Execute with SSL disabled
   relspec scripts execute --dir ./sql \
-                          --conn "postgres://user:pass@localhost/db?sslmode=disable"`,
+                          --conn "postgres://user:pass@localhost/db?sslmode=disable"
+
+  # Continue executing even if errors occur
+  relspec scripts execute --dir ./migrations \
+                          --conn "postgres://localhost/mydb" \
+                          --ignore-errors`,
 	RunE: runScriptsExecute,
 }
 
@@ -105,6 +111,7 @@ func init() {
 	scriptsExecuteCmd.Flags().StringVar(&scriptsConn, "conn", "", "PostgreSQL connection string (required)")
 	scriptsExecuteCmd.Flags().StringVar(&scriptsSchemaName, "schema", "public", "Schema name (optional, default: public)")
 	scriptsExecuteCmd.Flags().StringVar(&scriptsDBName, "database", "database", "Database name (optional, default: database)")
+	scriptsExecuteCmd.Flags().BoolVar(&scriptsIgnoreErrors, "ignore-errors", false, "Continue executing scripts even if errors occur")
 
 	err = scriptsExecuteCmd.MarkFlagRequired("dir")
 	if err != nil {
@@ -250,17 +257,39 @@ func runScriptsExecute(cmd *cobra.Command, args []string) error {
 	writer := sqlexec.NewWriter(&writers.WriterOptions{
 		Metadata: map[string]any{
 			"connection_string": scriptsConn,
+			"ignore_errors":     scriptsIgnoreErrors,
 		},
 	})
 
 	if err := writer.WriteSchema(schema); err != nil {
 		fmt.Fprintf(os.Stderr, "\n")
-		return fmt.Errorf("execution failed: %w", err)
+		return fmt.Errorf("script execution failed: %w", err)
+	}
+
+	// Get execution results from writer metadata
+	totalCount := len(schema.Scripts)
+	successCount := totalCount
+	failedCount := 0
+
+	opts := writer.Options()
+	if total, exists := opts.Metadata["execution_total"].(int); exists {
+		totalCount = total
+	}
+	if success, exists := opts.Metadata["execution_success"].(int); exists {
+		successCount = success
+	}
+	if failed, exists := opts.Metadata["execution_failed"].(int); exists {
+		failedCount = failed
 	}
 
 	fmt.Fprintf(os.Stderr, "\n=== Execution Complete ===\n")
 	fmt.Fprintf(os.Stderr, "Completed at: %s\n", getCurrentTimestamp())
-	fmt.Fprintf(os.Stderr, "Successfully executed %d script(s)\n\n", len(schema.Scripts))
+	fmt.Fprintf(os.Stderr, "Total scripts: %d\n", totalCount)
+	fmt.Fprintf(os.Stderr, "Successful:    %d\n", successCount)
+	if failedCount > 0 {
+		fmt.Fprintf(os.Stderr, "Failed:        %d\n", failedCount)
+	}
+	fmt.Fprintf(os.Stderr, "\n")
 
 	return nil
 }

cmd/relspec/split.go

@@ -183,7 +183,8 @@ func runSplit(cmd *cobra.Command, args []string) error {
 		splitTargetType,
 		splitTargetPath,
 		splitPackageName,
-		"", // no schema filter for split
+		"",    // no schema filter for split
+		false, // no flatten-schema for split
 	)
 	if err != nil {
 		return fmt.Errorf("failed to write output: %w", err)

doc.go

@@ -0,0 +1,108 @@
+// Package relspecgo provides bidirectional conversion between database schema formats.
+//
+// RelSpec is a comprehensive database schema tool that reads, writes, and transforms
+// database schemas across multiple formats including live databases, ORM models,
+// schema definition languages, and data interchange formats.
+//
+// # Features
+//
+//   - Read from 15+ formats: PostgreSQL, SQLite, DBML, GORM, Prisma, Drizzle, and more
+//   - Write to 15+ formats: SQL, ORM models, schema definitions, JSON/YAML
+//   - Interactive TUI editor for visual schema management
+//   - Schema diff and merge capabilities
+//   - Format-agnostic intermediate representation
+//
+// # Architecture
+//
+// RelSpec uses a hub-and-spoke architecture with models.Database as the central type:
+//
+//	Input Format → Reader → models.Database → Writer → Output Format
+//
+// This allows any supported input format to be converted to any supported output format
+// without requiring N² conversion implementations.
+//
+// # Key Packages
+//
+//   - pkg/models: Core data structures (Database, Schema, Table, Column, etc.)
+//   - pkg/readers: Input format readers (dbml, pgsql, gorm, etc.)
+//   - pkg/writers: Output format writers (dbml, pgsql, gorm, etc.)
+//   - pkg/ui: Interactive terminal UI for schema editing
+//   - pkg/diff: Schema comparison and difference detection
+//   - pkg/merge: Schema merging utilities
+//   - pkg/transform: Validation and normalization
+//
+// # Installation
+//
+//	go install git.warky.dev/wdevs/relspecgo/cmd/relspec@latest
+//
+// # Usage
+//
+// Command-line conversion:
+//
+//	relspec convert --from dbml --from-path schema.dbml \
+//	                --to gorm --to-path ./models
+//
+// Interactive editor:
+//
+//	relspec edit --from pgsql --from-conn "postgres://..." \
+//	             --to dbml --to-path schema.dbml
+//
+// Schema comparison:
+//
+//	relspec diff --source-type pgsql --source-conn "postgres://..." \
+//	             --target-type dbml --target-path schema.dbml
+//
+// Merge schemas:
+//
+//	relspec merge --target schema1.dbml --sources schema2.dbml,schema3.dbml
+//
+// # Supported Formats
+//
+// Input/Output Formats:
+//   - dbml: Database Markup Language
+//   - dctx: DCTX schema files
+//   - drawdb: DrawDB JSON format
+//   - graphql: GraphQL schema definition
+//   - json: JSON schema representation
+//   - yaml: YAML schema representation
+//   - gorm: Go GORM models
+//   - bun: Go Bun models
+//   - drizzle: TypeScript Drizzle ORM
+//   - prisma: Prisma schema language
+//   - typeorm: TypeScript TypeORM entities
+//   - pgsql: PostgreSQL (live DB or SQL)
+//   - sqlite: SQLite (database file or SQL)
+//
+// # Library Usage
+//
+// RelSpec can be used as a Go library:
+//
+//	import (
+//	    "git.warky.dev/wdevs/relspecgo/pkg/models"
+//	    "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+//	    "git.warky.dev/wdevs/relspecgo/pkg/writers/gorm"
+//	)
+//
+//	// Read DBML
+//	reader := dbml.NewReader(&readers.ReaderOptions{
+//	    FilePath: "schema.dbml",
+//	})
+//	db, err := reader.ReadDatabase()
+//
+//	// Write GORM models
+//	writer := gorm.NewWriter(&writers.WriterOptions{
+//	    OutputPath:  "./models",
+//	    PackageName: "models",
+//	})
+//	err = writer.WriteDatabase(db)
+//
+// # Documentation
+//
+// Full documentation available at: https://git.warky.dev/wdevs/relspecgo
+//
+// API documentation: go doc git.warky.dev/wdevs/relspecgo/...
+//
+// # License
+//
+// See LICENSE file in the repository root.
+package relspecgo

go.mod

@@ -12,10 +12,12 @@ require (
 	github.com/uptrace/bun v1.2.16
 	golang.org/x/text v0.28.0
 	gopkg.in/yaml.v3 v3.0.1
+	modernc.org/sqlite v1.44.3
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/gdamore/encoding v1.0.1 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
@@ -23,9 +25,12 @@ require (
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/puzpuzpuz/xsync/v3 v3.5.1 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/rogpeppe/go-internal v1.14.1 // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
@@ -33,6 +38,10 @@ require (
 	github.com/vmihailenco/msgpack/v5 v5.4.1 // indirect
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
 	golang.org/x/crypto v0.41.0 // indirect
+	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/term v0.34.0 // indirect
+	modernc.org/libc v1.67.6 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
 )

go.sum

@@ -3,13 +3,19 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/gdamore/encoding v1.0.1 h1:YzKZckdBL6jVt2Gc+5p82qhrGiqMdG/eNs6Wy0u3Uhw=
 github.com/gdamore/encoding v1.0.1/go.mod h1:0Z0cMFinngz9kS1QfMjCP8TY7em3bZYeeklsSDPivEo=
 github.com/gdamore/tcell/v2 v2.8.1 h1:KPNxyqclpWpWQlPLx6Xui1pMk8S+7+R37h3g07997NU=
 github.com/gdamore/tcell/v2 v2.8.1/go.mod h1:bj8ori1BG3OYMjmb3IklZVWfZUJ1UBQt9JXrOCOhGWw=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e h1:ijClszYn+mADRFY17kjQEVQ1XRhq2/JR1M3sGqeJoxs=
+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
+github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
@@ -28,13 +34,19 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
 github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
+github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/puzpuzpuz/xsync/v3 v3.5.1 h1:GJYJZwO6IdxN/IKbneznS6yPkVC+c3zyY/j19c++5Fg=
 github.com/puzpuzpuz/xsync/v3 v3.5.1/go.mod h1:VjzYrABPabuM4KyBh1Ftq6u8nhwY5tBPKP9jpmh0nnA=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/rivo/tview v0.42.0 h1:b/ftp+RxtDsHSaynXTbJb+/n/BxDEi+W3UfF5jILK6c=
 github.com/rivo/tview v0.42.0/go.mod h1:cSfIYfhpSGCjp3r/ECJb+GKS7cGJnqV8vfjQPwoXyfY=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
@@ -72,11 +84,15 @@ golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDf
 golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
 golang.org/x/crypto v0.41.0 h1:WKYxWedPGCTVVl5+WHSSrOBT0O8lx32+zxmHxijgXp4=
 golang.org/x/crypto v0.41.0/go.mod h1:pO5AFd7FA68rFak7rOAGVuygIISepHftHnr8dr6+sUc=
+golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2wtOnGAHZWCHUM4KGzY=
+golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
+golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
@@ -92,14 +108,15 @@ golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
-golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
+golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
@@ -135,6 +152,8 @@ golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
+golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=
+golang.org/x/tools v0.38.0/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
@@ -142,3 +161,31 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EV
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+modernc.org/cc/v4 v4.27.1 h1:9W30zRlYrefrDV2JE2O8VDtJ1yPGownxciz5rrbQZis=
+modernc.org/cc/v4 v4.27.1/go.mod h1:uVtb5OGqUKpoLWhqwNQo/8LwvoiEBLvZXIQ/SmO6mL0=
+modernc.org/ccgo/v4 v4.30.1 h1:4r4U1J6Fhj98NKfSjnPUN7Ze2c6MnAdL0hWw6+LrJpc=
+modernc.org/ccgo/v4 v4.30.1/go.mod h1:bIOeI1JL54Utlxn+LwrFyjCx2n2RDiYEaJVSrgdrRfM=
+modernc.org/fileutil v1.3.40 h1:ZGMswMNc9JOCrcrakF1HrvmergNLAmxOPjizirpfqBA=
+modernc.org/fileutil v1.3.40/go.mod h1:HxmghZSZVAz/LXcMNwZPA/DRrQZEVP9VX0V4LQGQFOc=
+modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
+modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
+modernc.org/gc/v3 v3.1.1 h1:k8T3gkXWY9sEiytKhcgyiZ2L0DTyCQ/nvX+LoCljoRE=
+modernc.org/gc/v3 v3.1.1/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
+modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
+modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
+modernc.org/libc v1.67.6 h1:eVOQvpModVLKOdT+LvBPjdQqfrZq+pC39BygcT+E7OI=
+modernc.org/libc v1.67.6/go.mod h1:JAhxUVlolfYDErnwiqaLvUqc8nfb2r6S6slAgZOnaiE=
+modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
+modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
+modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
+modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
+modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
+modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
+modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
+modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
+modernc.org/sqlite v1.44.3 h1:+39JvV/HWMcYslAwRxHb8067w+2zowvFOUrOWIy9PjY=
+modernc.org/sqlite v1.44.3/go.mod h1:CzbrU2lSB1DKUusvwGz7rqEKIq+NUd8GWuBBZDs9/nA=
+modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
+modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
+modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
+modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=

pkg/commontypes/commontypes_test.go

@@ -0,0 +1,714 @@
+package commontypes
+
+import (
+	"testing"
+)
+
+func TestExtractBaseType(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqlType string
+		want    string
+	}{
+		{"varchar with length", "varchar(100)", "varchar"},
+		{"VARCHAR uppercase with length", "VARCHAR(255)", "varchar"},
+		{"numeric with precision", "numeric(10,2)", "numeric"},
+		{"NUMERIC uppercase", "NUMERIC(18,4)", "numeric"},
+		{"decimal with precision", "decimal(15,3)", "decimal"},
+		{"char with length", "char(50)", "char"},
+		{"simple integer", "integer", "integer"},
+		{"simple text", "text", "text"},
+		{"bigint", "bigint", "bigint"},
+		{"With spaces", " varchar(100) ", "varchar"},
+		{"No parentheses", "boolean", "boolean"},
+		{"Empty string", "", ""},
+		{"Mixed case", "VarChar(100)", "varchar"},
+		{"timestamp with time zone", "timestamp(6) with time zone", "timestamp"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ExtractBaseType(tt.sqlType)
+			if got != tt.want {
+				t.Errorf("ExtractBaseType(%q) = %q, want %q", tt.sqlType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNormalizeType(t *testing.T) {
+	// NormalizeType is an alias for ExtractBaseType, test that they behave the same
+	testCases := []string{
+		"varchar(100)",
+		"numeric(10,2)",
+		"integer",
+		"text",
+		" VARCHAR(255) ",
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc, func(t *testing.T) {
+			extracted := ExtractBaseType(tc)
+			normalized := NormalizeType(tc)
+			if extracted != normalized {
+				t.Errorf("ExtractBaseType(%q) = %q, but NormalizeType(%q) = %q",
+					tc, extracted, tc, normalized)
+			}
+		})
+	}
+}
+
+func TestSQLToGo(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int32"},
+		{"bigint nullable", "bigint", true, "int64"},
+		{"smallint nullable", "smallint", true, "int16"},
+		{"serial nullable", "serial", true, "int32"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "*int32"},
+		{"bigint not nullable", "bigint", false, "*int64"},
+		{"smallint not nullable", "smallint", false, "*int16"},
+
+		// String types (nullable)
+		{"text nullable", "text", true, "string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar with length nullable", "varchar(100)", true, "string"},
+
+		// String types (not nullable)
+		{"text not nullable", "text", false, "*string"},
+		{"varchar not nullable", "varchar", false, "*string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "*bool"},
+
+		// Float types
+		{"real nullable", "real", true, "float32"},
+		{"double precision nullable", "double precision", true, "float64"},
+		{"real not nullable", "real", false, "*float32"},
+		{"double precision not nullable", "double precision", false, "*float64"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "time.Time"},
+		{"date nullable", "date", true, "time.Time"},
+		{"timestamp not nullable", "timestamp", false, "*time.Time"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "[]byte"},
+		{"bytea not nullable", "bytea", false, "[]byte"}, // Slices don't get pointer
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+		{"uuid not nullable", "uuid", false, "*string"},
+
+		// JSON
+		{"json nullable", "json", true, "string"},
+		{"jsonb nullable", "jsonb", true, "string"},
+
+		// Array
+		{"array nullable", "array", true, "[]string"},
+		{"array not nullable", "array", false, "[]string"}, // Slices don't get pointer
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "interface{}"},
+		{"unknown type not nullable", "unknowntype", false, "interface{}"}, // Interface doesn't get pointer
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToGo(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToGo(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToTypeScript(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types
+		{"integer nullable", "integer", true, "number"},
+		{"integer not nullable", "integer", false, "number | null"},
+		{"bigint nullable", "bigint", true, "number"},
+		{"bigint not nullable", "bigint", false, "number | null"},
+
+		// String types
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "string | null"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "boolean"},
+		{"boolean not nullable", "boolean", false, "boolean | null"},
+
+		// Float types
+		{"real nullable", "real", true, "number"},
+		{"double precision nullable", "double precision", true, "number"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "Date"},
+		{"date nullable", "date", true, "Date"},
+		{"timestamp not nullable", "timestamp", false, "Date | null"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "Buffer"},
+		{"bytea not nullable", "bytea", false, "Buffer | null"},
+
+		// JSON
+		{"json nullable", "json", true, "any"},
+		{"jsonb nullable", "jsonb", true, "any"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "any"},
+		{"unknown type not nullable", "unknowntype", false, "any | null"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToTypeScript(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToTypeScript(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToPython(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqlType string
+		want    string
+	}{
+		// Integer types
+		{"integer", "integer", "int"},
+		{"bigint", "bigint", "int"},
+		{"smallint", "smallint", "int"},
+
+		// String types
+		{"text", "text", "str"},
+		{"varchar", "varchar", "str"},
+		{"varchar(100)", "varchar(100)", "str"},
+
+		// Boolean
+		{"boolean", "boolean", "bool"},
+
+		// Float types
+		{"real", "real", "float"},
+		{"double precision", "double precision", "float"},
+		{"numeric", "numeric", "Decimal"},
+		{"decimal", "decimal", "Decimal"},
+
+		// Date/Time types
+		{"timestamp", "timestamp", "datetime"},
+		{"date", "date", "date"},
+		{"time", "time", "time"},
+
+		// Binary
+		{"bytea", "bytea", "bytes"},
+
+		// JSON
+		{"json", "json", "dict"},
+		{"jsonb", "jsonb", "dict"},
+
+		// UUID
+		{"uuid", "uuid", "UUID"},
+
+		// Array
+		{"array", "array", "list"},
+
+		// Unknown types
+		{"unknown type", "unknowntype", "Any"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToPython(tt.sqlType)
+			if got != tt.want {
+				t.Errorf("SQLToPython(%q) = %q, want %q", tt.sqlType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToCSharp(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int"},
+		{"bigint nullable", "bigint", true, "long"},
+		{"smallint nullable", "smallint", true, "short"},
+
+		// Integer types (not nullable - value types get ?)
+		{"integer not nullable", "integer", false, "int?"},
+		{"bigint not nullable", "bigint", false, "long?"},
+		{"smallint not nullable", "smallint", false, "short?"},
+
+		// String types (reference types, no ? needed)
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "bool?"},
+
+		// Float types
+		{"real nullable", "real", true, "float"},
+		{"double precision nullable", "double precision", true, "double"},
+		{"decimal nullable", "decimal", true, "decimal"},
+		{"real not nullable", "real", false, "float?"},
+		{"double precision not nullable", "double precision", false, "double?"},
+		{"decimal not nullable", "decimal", false, "decimal?"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "DateTime"},
+		{"date nullable", "date", true, "DateTime"},
+		{"timestamptz nullable", "timestamptz", true, "DateTimeOffset"},
+		{"timestamp not nullable", "timestamp", false, "DateTime?"},
+		{"timestamptz not nullable", "timestamptz", false, "DateTimeOffset?"},
+
+		// Binary (array type, no ?)
+		{"bytea nullable", "bytea", true, "byte[]"},
+		{"bytea not nullable", "bytea", false, "byte[]"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "Guid"},
+		{"uuid not nullable", "uuid", false, "Guid?"},
+
+		// JSON
+		{"json nullable", "json", true, "string"},
+
+		// Unknown types (object is reference type)
+		{"unknown type nullable", "unknowntype", true, "object"},
+		{"unknown type not nullable", "unknowntype", false, "object"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToCSharp(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToCSharp(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNeedsTimeImport(t *testing.T) {
+	tests := []struct {
+		name   string
+		goType string
+		want   bool
+	}{
+		{"time.Time type", "time.Time", true},
+		{"pointer to time.Time", "*time.Time", true},
+		{"int32 type", "int32", false},
+		{"string type", "string", false},
+		{"bool type", "bool", false},
+		{"[]byte type", "[]byte", false},
+		{"interface{}", "interface{}", false},
+		{"empty string", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := NeedsTimeImport(tt.goType)
+			if got != tt.want {
+				t.Errorf("NeedsTimeImport(%q) = %v, want %v", tt.goType, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGoTypeMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"integer":          "int32",
+		"bigint":           "int64",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "float64",
+		"bytea":            "[]byte",
+		"timestamp":        "time.Time",
+		"uuid":             "string",
+		"json":             "string",
+	}
+
+	for sqlType, expectedGoType := range expectedMappings {
+		if goType, ok := GoTypeMap[sqlType]; !ok {
+			t.Errorf("GoTypeMap missing entry for %q", sqlType)
+		} else if goType != expectedGoType {
+			t.Errorf("GoTypeMap[%q] = %q, want %q", sqlType, goType, expectedGoType)
+		}
+	}
+
+	if len(GoTypeMap) == 0 {
+		t.Error("GoTypeMap is empty")
+	}
+}
+
+func TestTypeScriptTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "number",
+		"bigint":           "number",
+		"text":             "string",
+		"boolean":          "boolean",
+		"double precision": "number",
+		"bytea":            "Buffer",
+		"timestamp":        "Date",
+		"uuid":             "string",
+		"json":             "any",
+	}
+
+	for sqlType, expectedTSType := range expectedMappings {
+		if tsType, ok := TypeScriptTypeMap[sqlType]; !ok {
+			t.Errorf("TypeScriptTypeMap missing entry for %q", sqlType)
+		} else if tsType != expectedTSType {
+			t.Errorf("TypeScriptTypeMap[%q] = %q, want %q", sqlType, tsType, expectedTSType)
+		}
+	}
+
+	if len(TypeScriptTypeMap) == 0 {
+		t.Error("TypeScriptTypeMap is empty")
+	}
+}
+
+func TestPythonTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer": "int",
+		"bigint":  "int",
+		"text":    "str",
+		"boolean": "bool",
+		"real":    "float",
+		"numeric": "Decimal",
+		"bytea":   "bytes",
+		"date":    "date",
+		"uuid":    "UUID",
+		"json":    "dict",
+	}
+
+	for sqlType, expectedPyType := range expectedMappings {
+		if pyType, ok := PythonTypeMap[sqlType]; !ok {
+			t.Errorf("PythonTypeMap missing entry for %q", sqlType)
+		} else if pyType != expectedPyType {
+			t.Errorf("PythonTypeMap[%q] = %q, want %q", sqlType, pyType, expectedPyType)
+		}
+	}
+
+	if len(PythonTypeMap) == 0 {
+		t.Error("PythonTypeMap is empty")
+	}
+}
+
+func TestCSharpTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "int",
+		"bigint":           "long",
+		"smallint":         "short",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "double",
+		"decimal":          "decimal",
+		"bytea":            "byte[]",
+		"timestamp":        "DateTime",
+		"uuid":             "Guid",
+		"json":             "string",
+	}
+
+	for sqlType, expectedCSType := range expectedMappings {
+		if csType, ok := CSharpTypeMap[sqlType]; !ok {
+			t.Errorf("CSharpTypeMap missing entry for %q", sqlType)
+		} else if csType != expectedCSType {
+			t.Errorf("CSharpTypeMap[%q] = %q, want %q", sqlType, csType, expectedCSType)
+		}
+	}
+
+	if len(CSharpTypeMap) == 0 {
+		t.Error("CSharpTypeMap is empty")
+	}
+}
+
+func TestSQLToJava(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types
+		{"integer nullable", "integer", true, "Integer"},
+		{"integer not nullable", "integer", false, "Integer"},
+		{"bigint nullable", "bigint", true, "Long"},
+		{"smallint nullable", "smallint", true, "Short"},
+
+		// String types
+		{"text nullable", "text", true, "String"},
+		{"varchar nullable", "varchar", true, "String"},
+		{"varchar(100) nullable", "varchar(100)", true, "String"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "Boolean"},
+
+		// Float types
+		{"real nullable", "real", true, "Float"},
+		{"double precision nullable", "double precision", true, "Double"},
+		{"numeric nullable", "numeric", true, "BigDecimal"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "Timestamp"},
+		{"date nullable", "date", true, "Date"},
+		{"time nullable", "time", true, "Time"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "byte[]"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "UUID"},
+
+		// JSON
+		{"json nullable", "json", true, "String"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "Object"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToJava(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToJava(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToPhp(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "int"},
+		{"bigint nullable", "bigint", true, "int"},
+		{"smallint nullable", "smallint", true, "int"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "?int"},
+		{"bigint not nullable", "bigint", false, "?int"},
+
+		// String types
+		{"text nullable", "text", true, "string"},
+		{"text not nullable", "text", false, "?string"},
+		{"varchar nullable", "varchar", true, "string"},
+		{"varchar(100) nullable", "varchar(100)", true, "string"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "?bool"},
+
+		// Float types
+		{"real nullable", "real", true, "float"},
+		{"double precision nullable", "double precision", true, "float"},
+		{"real not nullable", "real", false, "?float"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "\\DateTime"},
+		{"date nullable", "date", true, "\\DateTime"},
+		{"timestamp not nullable", "timestamp", false, "?\\DateTime"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "string"},
+		{"bytea not nullable", "bytea", false, "?string"},
+
+		// JSON
+		{"json nullable", "json", true, "array"},
+		{"json not nullable", "json", false, "?array"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "string"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "mixed"},
+		{"unknown type not nullable", "unknowntype", false, "mixed"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToPhp(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToPhp(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSQLToRust(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlType  string
+		nullable bool
+		want     string
+	}{
+		// Integer types (nullable)
+		{"integer nullable", "integer", true, "i32"},
+		{"bigint nullable", "bigint", true, "i64"},
+		{"smallint nullable", "smallint", true, "i16"},
+
+		// Integer types (not nullable)
+		{"integer not nullable", "integer", false, "Option<i32>"},
+		{"bigint not nullable", "bigint", false, "Option<i64>"},
+		{"smallint not nullable", "smallint", false, "Option<i16>"},
+
+		// String types
+		{"text nullable", "text", true, "String"},
+		{"text not nullable", "text", false, "Option<String>"},
+		{"varchar nullable", "varchar", true, "String"},
+		{"varchar(100) nullable", "varchar(100)", true, "String"},
+
+		// Boolean
+		{"boolean nullable", "boolean", true, "bool"},
+		{"boolean not nullable", "boolean", false, "Option<bool>"},
+
+		// Float types
+		{"real nullable", "real", true, "f32"},
+		{"double precision nullable", "double precision", true, "f64"},
+		{"real not nullable", "real", false, "Option<f32>"},
+		{"double precision not nullable", "double precision", false, "Option<f64>"},
+
+		// Date/Time types
+		{"timestamp nullable", "timestamp", true, "NaiveDateTime"},
+		{"timestamptz nullable", "timestamptz", true, "DateTime<Utc>"},
+		{"date nullable", "date", true, "NaiveDate"},
+		{"time nullable", "time", true, "NaiveTime"},
+		{"timestamp not nullable", "timestamp", false, "Option<NaiveDateTime>"},
+
+		// Binary
+		{"bytea nullable", "bytea", true, "Vec<u8>"},
+		{"bytea not nullable", "bytea", false, "Option<Vec<u8>>"},
+
+		// JSON
+		{"json nullable", "json", true, "serde_json::Value"},
+		{"json not nullable", "json", false, "Option<serde_json::Value>"},
+
+		// UUID
+		{"uuid nullable", "uuid", true, "String"},
+
+		// Unknown types
+		{"unknown type nullable", "unknowntype", true, "String"},
+		{"unknown type not nullable", "unknowntype", false, "Option<String>"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SQLToRust(tt.sqlType, tt.nullable)
+			if got != tt.want {
+				t.Errorf("SQLToRust(%q, %v) = %q, want %q", tt.sqlType, tt.nullable, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestJavaTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "Integer",
+		"bigint":           "Long",
+		"smallint":         "Short",
+		"text":             "String",
+		"boolean":          "Boolean",
+		"double precision": "Double",
+		"numeric":          "BigDecimal",
+		"bytea":            "byte[]",
+		"timestamp":        "Timestamp",
+		"uuid":             "UUID",
+		"date":             "Date",
+	}
+
+	for sqlType, expectedJavaType := range expectedMappings {
+		if javaType, ok := JavaTypeMap[sqlType]; !ok {
+			t.Errorf("JavaTypeMap missing entry for %q", sqlType)
+		} else if javaType != expectedJavaType {
+			t.Errorf("JavaTypeMap[%q] = %q, want %q", sqlType, javaType, expectedJavaType)
+		}
+	}
+
+	if len(JavaTypeMap) == 0 {
+		t.Error("JavaTypeMap is empty")
+	}
+}
+
+func TestPHPTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "int",
+		"bigint":           "int",
+		"text":             "string",
+		"boolean":          "bool",
+		"double precision": "float",
+		"bytea":            "string",
+		"timestamp":        "\\DateTime",
+		"uuid":             "string",
+		"json":             "array",
+	}
+
+	for sqlType, expectedPHPType := range expectedMappings {
+		if phpType, ok := PHPTypeMap[sqlType]; !ok {
+			t.Errorf("PHPTypeMap missing entry for %q", sqlType)
+		} else if phpType != expectedPHPType {
+			t.Errorf("PHPTypeMap[%q] = %q, want %q", sqlType, phpType, expectedPHPType)
+		}
+	}
+
+	if len(PHPTypeMap) == 0 {
+		t.Error("PHPTypeMap is empty")
+	}
+}
+
+func TestRustTypeMap(t *testing.T) {
+	expectedMappings := map[string]string{
+		"integer":          "i32",
+		"bigint":           "i64",
+		"smallint":         "i16",
+		"text":             "String",
+		"boolean":          "bool",
+		"double precision": "f64",
+		"real":             "f32",
+		"bytea":            "Vec<u8>",
+		"timestamp":        "NaiveDateTime",
+		"timestamptz":      "DateTime<Utc>",
+		"date":             "NaiveDate",
+		"json":             "serde_json::Value",
+	}
+
+	for sqlType, expectedRustType := range expectedMappings {
+		if rustType, ok := RustTypeMap[sqlType]; !ok {
+			t.Errorf("RustTypeMap missing entry for %q", sqlType)
+		} else if rustType != expectedRustType {
+			t.Errorf("RustTypeMap[%q] = %q, want %q", sqlType, rustType, expectedRustType)
+		}
+	}
+
+	if len(RustTypeMap) == 0 {
+		t.Error("RustTypeMap is empty")
+	}
+}

pkg/commontypes/doc.go

@@ -0,0 +1,28 @@
+// Package commontypes provides shared type definitions used across multiple packages.
+//
+// # Overview
+//
+// The commontypes package contains common data structures, constants, and type
+// definitions that are shared between different parts of RelSpec but don't belong
+// to the core models package.
+//
+// # Purpose
+//
+// This package helps avoid circular dependencies by providing a common location
+// for types that are used by multiple packages without creating import cycles.
+//
+// # Contents
+//
+// Common types may include:
+//   - Shared enums and constants
+//   - Utility type aliases
+//   - Common error types
+//   - Shared configuration structures
+//
+// # Usage
+//
+//	import "git.warky.dev/wdevs/relspecgo/pkg/commontypes"
+//
+//	// Use common types
+//	var formatType commontypes.FormatType
+package commontypes

pkg/diff/diff_test.go

@@ -0,0 +1,558 @@
+package diff
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestCompareDatabases(t *testing.T) {
+	tests := []struct {
+		name   string
+		source *models.Database
+		target *models.Database
+		want   func(*DiffResult) bool
+	}{
+		{
+			name: "identical databases",
+			source: &models.Database{
+				Name:    "source",
+				Schemas: []*models.Schema{},
+			},
+			target: &models.Database{
+				Name:    "target",
+				Schemas: []*models.Schema{},
+			},
+			want: func(r *DiffResult) bool {
+				return r.Source == "source" && r.Target == "target" &&
+					len(r.Schemas.Missing) == 0 && len(r.Schemas.Extra) == 0
+			},
+		},
+		{
+			name: "different schemas",
+			source: &models.Database{
+				Name: "source",
+				Schemas: []*models.Schema{
+					{Name: "public"},
+				},
+			},
+			target: &models.Database{
+				Name:    "target",
+				Schemas: []*models.Schema{},
+			},
+			want: func(r *DiffResult) bool {
+				return len(r.Schemas.Missing) == 1 && r.Schemas.Missing[0].Name == "public"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := CompareDatabases(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("CompareDatabases() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareColumns(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Column
+		target map[string]*models.Column
+		want   func(*ColumnDiff) bool
+	}{
+		{
+			name:   "identical columns",
+			source: map[string]*models.Column{},
+			target: map[string]*models.Column{},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing column",
+			source: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			target: map[string]*models.Column{},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "id"
+			},
+		},
+		{
+			name:   "extra column",
+			source: map[string]*models.Column{},
+			target: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "id"
+			},
+		},
+		{
+			name: "modified column type",
+			source: map[string]*models.Column{
+				"id": {Name: "id", Type: "integer"},
+			},
+			target: map[string]*models.Column{
+				"id": {Name: "id", Type: "bigint"},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "id" &&
+					d.Modified[0].Changes["type"] != nil
+			},
+		},
+		{
+			name: "modified column nullable",
+			source: map[string]*models.Column{
+				"name": {Name: "name", Type: "text", NotNull: true},
+			},
+			target: map[string]*models.Column{
+				"name": {Name: "name", Type: "text", NotNull: false},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Changes["not_null"] != nil
+			},
+		},
+		{
+			name: "modified column length",
+			source: map[string]*models.Column{
+				"name": {Name: "name", Type: "varchar", Length: 100},
+			},
+			target: map[string]*models.Column{
+				"name": {Name: "name", Type: "varchar", Length: 255},
+			},
+			want: func(d *ColumnDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Changes["length"] != nil
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareColumns(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareColumns() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareColumnDetails(t *testing.T) {
+	tests := []struct {
+		name   string
+		source *models.Column
+		target *models.Column
+		want   int // number of changes
+	}{
+		{
+			name:   "identical columns",
+			source: &models.Column{Name: "id", Type: "integer"},
+			target: &models.Column{Name: "id", Type: "integer"},
+			want:   0,
+		},
+		{
+			name:   "type change",
+			source: &models.Column{Name: "id", Type: "integer"},
+			target: &models.Column{Name: "id", Type: "bigint"},
+			want:   1,
+		},
+		{
+			name:   "length change",
+			source: &models.Column{Name: "name", Type: "varchar", Length: 100},
+			target: &models.Column{Name: "name", Type: "varchar", Length: 255},
+			want:   1,
+		},
+		{
+			name:   "precision change",
+			source: &models.Column{Name: "price", Type: "numeric", Precision: 10},
+			target: &models.Column{Name: "price", Type: "numeric", Precision: 12},
+			want:   1,
+		},
+		{
+			name:   "scale change",
+			source: &models.Column{Name: "price", Type: "numeric", Scale: 2},
+			target: &models.Column{Name: "price", Type: "numeric", Scale: 4},
+			want:   1,
+		},
+		{
+			name:   "not null change",
+			source: &models.Column{Name: "name", Type: "text", NotNull: true},
+			target: &models.Column{Name: "name", Type: "text", NotNull: false},
+			want:   1,
+		},
+		{
+			name:   "auto increment change",
+			source: &models.Column{Name: "id", Type: "integer", AutoIncrement: true},
+			target: &models.Column{Name: "id", Type: "integer", AutoIncrement: false},
+			want:   1,
+		},
+		{
+			name:   "primary key change",
+			source: &models.Column{Name: "id", Type: "integer", IsPrimaryKey: true},
+			target: &models.Column{Name: "id", Type: "integer", IsPrimaryKey: false},
+			want:   1,
+		},
+		{
+			name:   "multiple changes",
+			source: &models.Column{Name: "id", Type: "integer", NotNull: true, AutoIncrement: true},
+			target: &models.Column{Name: "id", Type: "bigint", NotNull: false, AutoIncrement: false},
+			want:   3,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareColumnDetails(tt.source, tt.target)
+			if len(got) != tt.want {
+				t.Errorf("compareColumnDetails() = %d changes, want %d", len(got), tt.want)
+			}
+		})
+	}
+}
+
+func TestCompareIndexes(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Index
+		target map[string]*models.Index
+		want   func(*IndexDiff) bool
+	}{
+		{
+			name:   "identical indexes",
+			source: map[string]*models.Index{},
+			target: map[string]*models.Index{},
+			want: func(d *IndexDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing index",
+			source: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}},
+			},
+			target: map[string]*models.Index{},
+			want: func(d *IndexDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "idx_name"
+			},
+		},
+		{
+			name:   "extra index",
+			source: map[string]*models.Index{},
+			target: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}},
+			},
+			want: func(d *IndexDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "idx_name"
+			},
+		},
+		{
+			name: "modified index uniqueness",
+			source: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}, Unique: false},
+			},
+			target: map[string]*models.Index{
+				"idx_name": {Name: "idx_name", Columns: []string{"name"}, Unique: true},
+			},
+			want: func(d *IndexDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "idx_name"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareIndexes(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareIndexes() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareConstraints(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Constraint
+		target map[string]*models.Constraint
+		want   func(*ConstraintDiff) bool
+	}{
+		{
+			name:   "identical constraints",
+			source: map[string]*models.Constraint{},
+			target: map[string]*models.Constraint{},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing constraint",
+			source: map[string]*models.Constraint{
+				"pk_id": {Name: "pk_id", Type: "PRIMARY KEY", Columns: []string{"id"}},
+			},
+			target: map[string]*models.Constraint{},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "pk_id"
+			},
+		},
+		{
+			name:   "extra constraint",
+			source: map[string]*models.Constraint{},
+			target: map[string]*models.Constraint{
+				"pk_id": {Name: "pk_id", Type: "PRIMARY KEY", Columns: []string{"id"}},
+			},
+			want: func(d *ConstraintDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "pk_id"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareConstraints(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareConstraints() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareRelationships(t *testing.T) {
+	tests := []struct {
+		name   string
+		source map[string]*models.Relationship
+		target map[string]*models.Relationship
+		want   func(*RelationshipDiff) bool
+	}{
+		{
+			name:   "identical relationships",
+			source: map[string]*models.Relationship{},
+			target: map[string]*models.Relationship{},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing relationship",
+			source: map[string]*models.Relationship{
+				"fk_user": {Name: "fk_user", Type: "FOREIGN KEY"},
+			},
+			target: map[string]*models.Relationship{},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "fk_user"
+			},
+		},
+		{
+			name:   "extra relationship",
+			source: map[string]*models.Relationship{},
+			target: map[string]*models.Relationship{
+				"fk_user": {Name: "fk_user", Type: "FOREIGN KEY"},
+			},
+			want: func(d *RelationshipDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "fk_user"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareRelationships(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareRelationships() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareTables(t *testing.T) {
+	tests := []struct {
+		name   string
+		source []*models.Table
+		target []*models.Table
+		want   func(*TableDiff) bool
+	}{
+		{
+			name:   "identical tables",
+			source: []*models.Table{},
+			target: []*models.Table{},
+			want: func(d *TableDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing table",
+			source: []*models.Table{
+				{Name: "users", Schema: "public"},
+			},
+			target: []*models.Table{},
+			want: func(d *TableDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "users"
+			},
+		},
+		{
+			name:   "extra table",
+			source: []*models.Table{},
+			target: []*models.Table{
+				{Name: "users", Schema: "public"},
+			},
+			want: func(d *TableDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "users"
+			},
+		},
+		{
+			name: "modified table",
+			source: []*models.Table{
+				{
+					Name:   "users",
+					Schema: "public",
+					Columns: map[string]*models.Column{
+						"id": {Name: "id", Type: "integer"},
+					},
+				},
+			},
+			target: []*models.Table{
+				{
+					Name:   "users",
+					Schema: "public",
+					Columns: map[string]*models.Column{
+						"id": {Name: "id", Type: "bigint"},
+					},
+				},
+			},
+			want: func(d *TableDiff) bool {
+				return len(d.Modified) == 1 && d.Modified[0].Name == "users"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareTables(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareTables() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestCompareSchemas(t *testing.T) {
+	tests := []struct {
+		name   string
+		source []*models.Schema
+		target []*models.Schema
+		want   func(*SchemaDiff) bool
+	}{
+		{
+			name:   "identical schemas",
+			source: []*models.Schema{},
+			target: []*models.Schema{},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Missing) == 0 && len(d.Extra) == 0 && len(d.Modified) == 0
+			},
+		},
+		{
+			name: "missing schema",
+			source: []*models.Schema{
+				{Name: "public"},
+			},
+			target: []*models.Schema{},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Missing) == 1 && d.Missing[0].Name == "public"
+			},
+		},
+		{
+			name:   "extra schema",
+			source: []*models.Schema{},
+			target: []*models.Schema{
+				{Name: "public"},
+			},
+			want: func(d *SchemaDiff) bool {
+				return len(d.Extra) == 1 && d.Extra[0].Name == "public"
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareSchemas(tt.source, tt.target)
+			if !tt.want(got) {
+				t.Errorf("compareSchemas() result doesn't match expectations")
+			}
+		})
+	}
+}
+
+func TestIsEmpty(t *testing.T) {
+	tests := []struct {
+		name string
+		v    interface{}
+		want bool
+	}{
+		{"empty ColumnDiff", &ColumnDiff{Missing: []*models.Column{}, Extra: []*models.Column{}, Modified: []*ColumnChange{}}, true},
+		{"ColumnDiff with missing", &ColumnDiff{Missing: []*models.Column{{Name: "id"}}, Extra: []*models.Column{}, Modified: []*ColumnChange{}}, false},
+		{"ColumnDiff with extra", &ColumnDiff{Missing: []*models.Column{}, Extra: []*models.Column{{Name: "id"}}, Modified: []*ColumnChange{}}, false},
+		{"empty IndexDiff", &IndexDiff{Missing: []*models.Index{}, Extra: []*models.Index{}, Modified: []*IndexChange{}}, true},
+		{"IndexDiff with missing", &IndexDiff{Missing: []*models.Index{{Name: "idx"}}, Extra: []*models.Index{}, Modified: []*IndexChange{}}, false},
+		{"empty TableDiff", &TableDiff{Missing: []*models.Table{}, Extra: []*models.Table{}, Modified: []*TableChange{}}, true},
+		{"TableDiff with extra", &TableDiff{Missing: []*models.Table{}, Extra: []*models.Table{{Name: "users"}}, Modified: []*TableChange{}}, false},
+		{"empty ConstraintDiff", &ConstraintDiff{Missing: []*models.Constraint{}, Extra: []*models.Constraint{}, Modified: []*ConstraintChange{}}, true},
+		{"empty RelationshipDiff", &RelationshipDiff{Missing: []*models.Relationship{}, Extra: []*models.Relationship{}, Modified: []*RelationshipChange{}}, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := isEmpty(tt.v)
+			if got != tt.want {
+				t.Errorf("isEmpty() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestComputeSummary(t *testing.T) {
+	tests := []struct {
+		name   string
+		result *DiffResult
+		want   func(*Summary) bool
+	}{
+		{
+			name: "empty diff",
+			result: &DiffResult{
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			want: func(s *Summary) bool {
+				return s.Schemas.Missing == 0 && s.Schemas.Extra == 0 && s.Schemas.Modified == 0
+			},
+		},
+		{
+			name: "schemas with differences",
+			result: &DiffResult{
+				Schemas: &SchemaDiff{
+					Missing: []*models.Schema{{Name: "schema1"}},
+					Extra:   []*models.Schema{{Name: "schema2"}, {Name: "schema3"}},
+					Modified: []*SchemaChange{
+						{Name: "public"},
+					},
+				},
+			},
+			want: func(s *Summary) bool {
+				return s.Schemas.Missing == 1 && s.Schemas.Extra == 2 && s.Schemas.Modified == 1
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ComputeSummary(tt.result)
+			if !tt.want(got) {
+				t.Errorf("ComputeSummary() result doesn't match expectations")
+			}
+		})
+	}
+}

pkg/diff/doc.go

@@ -0,0 +1,43 @@
+// Package diff provides utilities for comparing database schemas and identifying differences.
+//
+// # Overview
+//
+// The diff package compares two database models at various granularity levels (database,
+// schema, table, column) and produces detailed reports of differences including:
+//   - Missing items (present in source but not in target)
+//   - Extra items (present in target but not in source)
+//   - Modified items (present in both but with different properties)
+//
+// # Usage
+//
+// Compare two databases and format the output:
+//
+//	result := diff.CompareDatabases(sourceDB, targetDB)
+//	err := diff.FormatDiff(result, diff.OutputFormatText, os.Stdout)
+//
+// # Output Formats
+//
+// The package supports multiple output formats:
+//   - OutputFormatText: Human-readable text format
+//   - OutputFormatJSON: Structured JSON output
+//   - OutputFormatYAML: Structured YAML output
+//
+// # Comparison Scope
+//
+// The comparison covers:
+//   - Schemas: Name, description, and contents
+//   - Tables: Name, description, and all sub-elements
+//   - Columns: Type, nullability, defaults, constraints
+//   - Indexes: Columns, uniqueness, type
+//   - Constraints: Type, columns, references
+//   - Relationships: Type, from/to tables and columns
+//   - Views: Definition and columns
+//   - Sequences: Start value, increment, min/max values
+//
+// # Use Cases
+//
+//   - Schema migration planning
+//   - Database synchronization verification
+//   - Change tracking and auditing
+//   - CI/CD pipeline validation
+package diff

pkg/diff/formatters_test.go

@@ -0,0 +1,440 @@
+package diff
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestFormatDiff(t *testing.T) {
+	result := &DiffResult{
+		Source: "source_db",
+		Target: "target_db",
+		Schemas: &SchemaDiff{
+			Missing:  []*models.Schema{},
+			Extra:    []*models.Schema{},
+			Modified: []*SchemaChange{},
+		},
+	}
+
+	tests := []struct {
+		name    string
+		format  OutputFormat
+		wantErr bool
+	}{
+		{"summary format", FormatSummary, false},
+		{"json format", FormatJSON, false},
+		{"html format", FormatHTML, false},
+		{"invalid format", OutputFormat("invalid"), true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := FormatDiff(result, tt.format, &buf)
+
+			if (err != nil) != tt.wantErr {
+				t.Errorf("FormatDiff() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			if !tt.wantErr && buf.Len() == 0 {
+				t.Error("FormatDiff() produced empty output")
+			}
+		})
+	}
+}
+
+func TestFormatSummary(t *testing.T) {
+	tests := []struct {
+		name    string
+		result  *DiffResult
+		wantStr []string // strings that should appear in output
+	}{
+		{
+			name: "no differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{"source", "target", "No differences found"},
+		},
+		{
+			name: "with schema differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing: []*models.Schema{{Name: "schema1"}},
+					Extra:   []*models.Schema{{Name: "schema2"}},
+					Modified: []*SchemaChange{
+						{Name: "public"},
+					},
+				},
+			},
+			wantStr: []string{"Schemas:", "Missing:  1", "Extra:    1", "Modified: 1"},
+		},
+		{
+			name: "with table differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Modified: []*SchemaChange{
+						{
+							Name: "public",
+							Tables: &TableDiff{
+								Missing: []*models.Table{{Name: "users"}},
+								Extra:   []*models.Table{{Name: "posts"}},
+								Modified: []*TableChange{
+									{Name: "comments", Schema: "public"},
+								},
+							},
+						},
+					},
+				},
+			},
+			wantStr: []string{"Tables:", "Missing:  1", "Extra:    1", "Modified: 1"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := formatSummary(tt.result, &buf)
+
+			if err != nil {
+				t.Errorf("formatSummary() error = %v", err)
+				return
+			}
+
+			output := buf.String()
+			for _, want := range tt.wantStr {
+				if !strings.Contains(output, want) {
+					t.Errorf("formatSummary() output doesn't contain %q\nGot: %s", want, output)
+				}
+			}
+		})
+	}
+}
+
+func TestFormatJSON(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Missing:  []*models.Schema{{Name: "schema1"}},
+			Extra:    []*models.Schema{},
+			Modified: []*SchemaChange{},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatJSON(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatJSON() error = %v", err)
+		return
+	}
+
+	// Check if output is valid JSON
+	var decoded DiffResult
+	if err := json.Unmarshal(buf.Bytes(), &decoded); err != nil {
+		t.Errorf("formatJSON() produced invalid JSON: %v", err)
+	}
+
+	// Check basic structure
+	if decoded.Source != "source" {
+		t.Errorf("formatJSON() source = %v, want %v", decoded.Source, "source")
+	}
+	if decoded.Target != "target" {
+		t.Errorf("formatJSON() target = %v, want %v", decoded.Target, "target")
+	}
+	if len(decoded.Schemas.Missing) != 1 {
+		t.Errorf("formatJSON() missing schemas = %v, want 1", len(decoded.Schemas.Missing))
+	}
+}
+
+func TestFormatHTML(t *testing.T) {
+	tests := []struct {
+		name    string
+		result  *DiffResult
+		wantStr []string // HTML elements/content that should appear
+	}{
+		{
+			name: "basic HTML structure",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{},
+					Extra:    []*models.Schema{},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{
+				"<!DOCTYPE html>",
+				"<title>Database Diff Report</title>",
+				"source",
+				"target",
+			},
+		},
+		{
+			name: "with schema differences",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Missing:  []*models.Schema{{Name: "missing_schema"}},
+					Extra:    []*models.Schema{{Name: "extra_schema"}},
+					Modified: []*SchemaChange{},
+				},
+			},
+			wantStr: []string{
+				"<!DOCTYPE html>",
+				"missing_schema",
+				"extra_schema",
+				"MISSING",
+				"EXTRA",
+			},
+		},
+		{
+			name: "with table modifications",
+			result: &DiffResult{
+				Source: "source",
+				Target: "target",
+				Schemas: &SchemaDiff{
+					Modified: []*SchemaChange{
+						{
+							Name: "public",
+							Tables: &TableDiff{
+								Modified: []*TableChange{
+									{
+										Name:   "users",
+										Schema: "public",
+										Columns: &ColumnDiff{
+											Missing: []*models.Column{{Name: "email", Type: "text"}},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			wantStr: []string{
+				"public",
+				"users",
+				"email",
+				"text",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			err := formatHTML(tt.result, &buf)
+
+			if err != nil {
+				t.Errorf("formatHTML() error = %v", err)
+				return
+			}
+
+			output := buf.String()
+			for _, want := range tt.wantStr {
+				if !strings.Contains(output, want) {
+					t.Errorf("formatHTML() output doesn't contain %q", want)
+				}
+			}
+		})
+	}
+}
+
+func TestFormatSummaryWithColumns(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Columns: &ColumnDiff{
+									Missing: []*models.Column{{Name: "email"}},
+									Extra:   []*models.Column{{Name: "phone"}, {Name: "address"}},
+									Modified: []*ColumnChange{
+										{Name: "name"},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	wantStrings := []string{
+		"Columns:",
+		"Missing:  1",
+		"Extra:    2",
+		"Modified: 1",
+	}
+
+	for _, want := range wantStrings {
+		if !strings.Contains(output, want) {
+			t.Errorf("formatSummary() output doesn't contain %q\nGot: %s", want, output)
+		}
+	}
+}
+
+func TestFormatSummaryWithIndexes(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Indexes: &IndexDiff{
+									Missing:  []*models.Index{{Name: "idx_email"}},
+									Extra:    []*models.Index{{Name: "idx_phone"}},
+									Modified: []*IndexChange{{Name: "idx_name"}},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "Indexes:") {
+		t.Error("formatSummary() output doesn't contain Indexes section")
+	}
+	if !strings.Contains(output, "Missing:  1") {
+		t.Error("formatSummary() output doesn't contain correct missing count")
+	}
+}
+
+func TestFormatSummaryWithConstraints(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Modified: []*SchemaChange{
+				{
+					Name: "public",
+					Tables: &TableDiff{
+						Modified: []*TableChange{
+							{
+								Name:   "users",
+								Schema: "public",
+								Constraints: &ConstraintDiff{
+									Missing: []*models.Constraint{{Name: "pk_users", Type: "PRIMARY KEY"}},
+									Extra:   []*models.Constraint{{Name: "fk_users_roles", Type: "FOREIGN KEY"}},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatSummary(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatSummary() error = %v", err)
+		return
+	}
+
+	output := buf.String()
+	if !strings.Contains(output, "Constraints:") {
+		t.Error("formatSummary() output doesn't contain Constraints section")
+	}
+}
+
+func TestFormatJSONIndentation(t *testing.T) {
+	result := &DiffResult{
+		Source: "source",
+		Target: "target",
+		Schemas: &SchemaDiff{
+			Missing: []*models.Schema{{Name: "test"}},
+		},
+	}
+
+	var buf bytes.Buffer
+	err := formatJSON(result, &buf)
+
+	if err != nil {
+		t.Errorf("formatJSON() error = %v", err)
+		return
+	}
+
+	// Check that JSON is indented (has newlines and spaces)
+	output := buf.String()
+	if !strings.Contains(output, "\n") {
+		t.Error("formatJSON() should produce indented JSON with newlines")
+	}
+	if !strings.Contains(output, "  ") {
+		t.Error("formatJSON() should produce indented JSON with spaces")
+	}
+}
+
+func TestOutputFormatConstants(t *testing.T) {
+	tests := []struct {
+		name   string
+		format OutputFormat
+		want   string
+	}{
+		{"summary constant", FormatSummary, "summary"},
+		{"json constant", FormatJSON, "json"},
+		{"html constant", FormatHTML, "html"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if string(tt.format) != tt.want {
+				t.Errorf("OutputFormat %v = %v, want %v", tt.name, tt.format, tt.want)
+			}
+		})
+	}
+}

pkg/inspector/doc.go

@@ -0,0 +1,40 @@
+// Package inspector provides database introspection capabilities for live databases.
+//
+// # Overview
+//
+// The inspector package contains utilities for connecting to live databases and
+// extracting their schema information through system catalog queries and metadata
+// inspection.
+//
+// # Features
+//
+//   - Database connection management
+//   - Schema metadata extraction
+//   - Table structure analysis
+//   - Constraint and index discovery
+//   - Foreign key relationship mapping
+//
+// # Supported Databases
+//
+//   - PostgreSQL (via pgx driver)
+//   - SQLite (via modernc.org/sqlite driver)
+//
+// # Usage
+//
+// This package is used internally by database readers (pgsql, sqlite) to perform
+// live schema introspection:
+//
+//	inspector := inspector.NewPostgreSQLInspector(connString)
+//	schemas, err := inspector.GetSchemas()
+//	tables, err := inspector.GetTables(schemaName)
+//
+// # Architecture
+//
+// Each database type has its own inspector implementation that understands the
+// specific system catalogs and metadata structures of that database system.
+//
+// # Security
+//
+// Inspectors use read-only operations and never modify database structure.
+// Connection credentials should be handled securely.
+package inspector

pkg/inspector/inspector_test.go

@@ -0,0 +1,238 @@
+package inspector
+
+import (
+	"testing"
+)
+
+func TestNewInspector(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	inspector := NewInspector(db, config)
+
+	if inspector == nil {
+		t.Fatal("NewInspector() returned nil")
+	}
+
+	if inspector.db != db {
+		t.Error("NewInspector() database not set correctly")
+	}
+
+	if inspector.config != config {
+		t.Error("NewInspector() config not set correctly")
+	}
+}
+
+func TestInspect(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() returned error: %v", err)
+	}
+
+	if report == nil {
+		t.Fatal("Inspect() returned nil report")
+	}
+
+	if report.Database != db.Name {
+		t.Errorf("Inspect() report.Database = %q, want %q", report.Database, db.Name)
+	}
+
+	if report.Summary.TotalRules != len(config.Rules) {
+		t.Errorf("Inspect() TotalRules = %d, want %d", report.Summary.TotalRules, len(config.Rules))
+	}
+
+	if len(report.Violations) == 0 {
+		t.Error("Inspect() returned no violations, expected some results")
+	}
+}
+
+func TestInspectWithDisabledRules(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	// Disable all rules
+	for name := range config.Rules {
+		rule := config.Rules[name]
+		rule.Enabled = "off"
+		config.Rules[name] = rule
+	}
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() with disabled rules returned error: %v", err)
+	}
+
+	if report.Summary.RulesChecked != 0 {
+		t.Errorf("Inspect() RulesChecked = %d, want 0 (all disabled)", report.Summary.RulesChecked)
+	}
+
+	if report.Summary.RulesSkipped != len(config.Rules) {
+		t.Errorf("Inspect() RulesSkipped = %d, want %d", report.Summary.RulesSkipped, len(config.Rules))
+	}
+}
+
+func TestInspectWithEnforcedRules(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+
+	// Enable only one rule and enforce it
+	for name := range config.Rules {
+		rule := config.Rules[name]
+		rule.Enabled = "off"
+		config.Rules[name] = rule
+	}
+
+	primaryKeyRule := config.Rules["primary_key_naming"]
+	primaryKeyRule.Enabled = "enforce"
+	primaryKeyRule.Pattern = "^id$"
+	config.Rules["primary_key_naming"] = primaryKeyRule
+
+	inspector := NewInspector(db, config)
+	report, err := inspector.Inspect()
+
+	if err != nil {
+		t.Fatalf("Inspect() returned error: %v", err)
+	}
+
+	if report.Summary.RulesChecked != 1 {
+		t.Errorf("Inspect() RulesChecked = %d, want 1", report.Summary.RulesChecked)
+	}
+
+	// All results should be at error level for enforced rules
+	for _, violation := range report.Violations {
+		if violation.Level != "error" {
+			t.Errorf("Enforced rule violation has Level = %q, want \"error\"", violation.Level)
+		}
+	}
+}
+
+func TestGenerateSummary(t *testing.T) {
+	db := createTestDatabase()
+	config := GetDefaultConfig()
+	inspector := NewInspector(db, config)
+
+	results := []ValidationResult{
+		{RuleName: "rule1", Passed: true, Level: "error"},
+		{RuleName: "rule2", Passed: false, Level: "error"},
+		{RuleName: "rule3", Passed: false, Level: "warning"},
+		{RuleName: "rule4", Passed: true, Level: "warning"},
+	}
+
+	summary := inspector.generateSummary(results)
+
+	if summary.PassedCount != 2 {
+		t.Errorf("generateSummary() PassedCount = %d, want 2", summary.PassedCount)
+	}
+
+	if summary.ErrorCount != 1 {
+		t.Errorf("generateSummary() ErrorCount = %d, want 1", summary.ErrorCount)
+	}
+
+	if summary.WarningCount != 1 {
+		t.Errorf("generateSummary() WarningCount = %d, want 1", summary.WarningCount)
+	}
+}
+
+func TestHasErrors(t *testing.T) {
+	tests := []struct {
+		name   string
+		report *InspectorReport
+		want   bool
+	}{
+		{
+			name: "with errors",
+			report: &InspectorReport{
+				Summary: ReportSummary{
+					ErrorCount: 5,
+				},
+			},
+			want: true,
+		},
+		{
+			name: "without errors",
+			report: &InspectorReport{
+				Summary: ReportSummary{
+					ErrorCount:   0,
+					WarningCount: 3,
+				},
+			},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.report.HasErrors(); got != tt.want {
+				t.Errorf("HasErrors() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetValidator(t *testing.T) {
+	tests := []struct {
+		name         string
+		functionName string
+		wantExists   bool
+	}{
+		{"primary_key_naming", "primary_key_naming", true},
+		{"primary_key_datatype", "primary_key_datatype", true},
+		{"foreign_key_column_naming", "foreign_key_column_naming", true},
+		{"table_regexpr", "table_regexpr", true},
+		{"column_regexpr", "column_regexpr", true},
+		{"reserved_words", "reserved_words", true},
+		{"have_primary_key", "have_primary_key", true},
+		{"orphaned_foreign_key", "orphaned_foreign_key", true},
+		{"circular_dependency", "circular_dependency", true},
+		{"unknown_function", "unknown_function", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, exists := getValidator(tt.functionName)
+			if exists != tt.wantExists {
+				t.Errorf("getValidator(%q) exists = %v, want %v", tt.functionName, exists, tt.wantExists)
+			}
+		})
+	}
+}
+
+func TestCreateResult(t *testing.T) {
+	result := createResult(
+		"test_rule",
+		true,
+		"Test message",
+		"schema.table.column",
+		map[string]interface{}{
+			"key1": "value1",
+			"key2": 42,
+		},
+	)
+
+	if result.RuleName != "test_rule" {
+		t.Errorf("createResult() RuleName = %q, want \"test_rule\"", result.RuleName)
+	}
+
+	if !result.Passed {
+		t.Error("createResult() Passed = false, want true")
+	}
+
+	if result.Message != "Test message" {
+		t.Errorf("createResult() Message = %q, want \"Test message\"", result.Message)
+	}
+
+	if result.Location != "schema.table.column" {
+		t.Errorf("createResult() Location = %q, want \"schema.table.column\"", result.Location)
+	}
+
+	if len(result.Context) != 2 {
+		t.Errorf("createResult() Context length = %d, want 2", len(result.Context))
+	}
+}

pkg/inspector/report_test.go

@@ -0,0 +1,366 @@
+package inspector
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+)
+
+func createTestReport() *InspectorReport {
+	return &InspectorReport{
+		Summary: ReportSummary{
+			TotalRules:   10,
+			RulesChecked: 8,
+			RulesSkipped: 2,
+			ErrorCount:   3,
+			WarningCount: 5,
+			PassedCount:  12,
+		},
+		Violations: []ValidationResult{
+			{
+				RuleName: "primary_key_naming",
+				Level:    "error",
+				Message:  "Primary key should start with 'id_'",
+				Location: "public.users.user_id",
+				Passed:   false,
+				Context: map[string]interface{}{
+					"schema":  "public",
+					"table":   "users",
+					"column":  "user_id",
+					"pattern": "^id_",
+				},
+			},
+			{
+				RuleName: "table_name_length",
+				Level:    "warning",
+				Message:  "Table name too long",
+				Location: "public.very_long_table_name_that_exceeds_limits",
+				Passed:   false,
+				Context: map[string]interface{}{
+					"schema":     "public",
+					"table":      "very_long_table_name_that_exceeds_limits",
+					"length":     44,
+					"max_length": 32,
+				},
+			},
+		},
+		GeneratedAt:  time.Now(),
+		Database:     "testdb",
+		SourceFormat: "postgresql",
+	}
+}
+
+func TestNewMarkdownFormatter(t *testing.T) {
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	if formatter == nil {
+		t.Fatal("NewMarkdownFormatter() returned nil")
+	}
+
+	// Buffer is not a terminal, so colors should be disabled
+	if formatter.UseColors {
+		t.Error("NewMarkdownFormatter() UseColors should be false for non-terminal")
+	}
+}
+
+func TestNewJSONFormatter(t *testing.T) {
+	formatter := NewJSONFormatter()
+
+	if formatter == nil {
+		t.Fatal("NewJSONFormatter() returned nil")
+	}
+}
+
+func TestMarkdownFormatter_Format(t *testing.T) {
+	report := createTestReport()
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("MarkdownFormatter.Format() returned error: %v", err)
+	}
+
+	// Check that output contains expected sections
+	if !strings.Contains(output, "# RelSpec Inspector Report") {
+		t.Error("Markdown output missing header")
+	}
+
+	if !strings.Contains(output, "Database:") {
+		t.Error("Markdown output missing database field")
+	}
+
+	if !strings.Contains(output, "testdb") {
+		t.Error("Markdown output missing database name")
+	}
+
+	if !strings.Contains(output, "Summary") {
+		t.Error("Markdown output missing summary section")
+	}
+
+	if !strings.Contains(output, "Rules Checked: 8") {
+		t.Error("Markdown output missing rules checked count")
+	}
+
+	if !strings.Contains(output, "Errors: 3") {
+		t.Error("Markdown output missing error count")
+	}
+
+	if !strings.Contains(output, "Warnings: 5") {
+		t.Error("Markdown output missing warning count")
+	}
+
+	if !strings.Contains(output, "Violations") {
+		t.Error("Markdown output missing violations section")
+	}
+
+	if !strings.Contains(output, "primary_key_naming") {
+		t.Error("Markdown output missing rule name")
+	}
+
+	if !strings.Contains(output, "public.users.user_id") {
+		t.Error("Markdown output missing location")
+	}
+}
+
+func TestMarkdownFormatter_FormatNoViolations(t *testing.T) {
+	report := &InspectorReport{
+		Summary: ReportSummary{
+			TotalRules:   10,
+			RulesChecked: 10,
+			RulesSkipped: 0,
+			ErrorCount:   0,
+			WarningCount: 0,
+			PassedCount:  50,
+		},
+		Violations:   []ValidationResult{},
+		GeneratedAt:  time.Now(),
+		Database:     "testdb",
+		SourceFormat: "postgresql",
+	}
+
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("MarkdownFormatter.Format() returned error: %v", err)
+	}
+
+	if !strings.Contains(output, "No violations found") {
+		t.Error("Markdown output should indicate no violations")
+	}
+}
+
+func TestJSONFormatter_Format(t *testing.T) {
+	report := createTestReport()
+	formatter := NewJSONFormatter()
+
+	output, err := formatter.Format(report)
+	if err != nil {
+		t.Fatalf("JSONFormatter.Format() returned error: %v", err)
+	}
+
+	// Verify it's valid JSON
+	var decoded InspectorReport
+	if err := json.Unmarshal([]byte(output), &decoded); err != nil {
+		t.Fatalf("JSONFormatter.Format() produced invalid JSON: %v", err)
+	}
+
+	// Check key fields
+	if decoded.Database != "testdb" {
+		t.Errorf("JSON decoded Database = %q, want \"testdb\"", decoded.Database)
+	}
+
+	if decoded.Summary.ErrorCount != 3 {
+		t.Errorf("JSON decoded ErrorCount = %d, want 3", decoded.Summary.ErrorCount)
+	}
+
+	if len(decoded.Violations) != 2 {
+		t.Errorf("JSON decoded Violations length = %d, want 2", len(decoded.Violations))
+	}
+}
+
+func TestMarkdownFormatter_FormatHeader(t *testing.T) {
+	var buf bytes.Buffer
+	formatter := NewMarkdownFormatter(&buf)
+
+	header := formatter.formatHeader("Test Header")
+
+	if !strings.Contains(header, "# Test Header") {
+		t.Errorf("formatHeader() = %q, want to contain \"# Test Header\"", header)
+	}
+}
+
+func TestMarkdownFormatter_FormatBold(t *testing.T) {
+	tests := []struct {
+		name         string
+		useColors    bool
+		text         string
+		wantContains string
+	}{
+		{
+			name:         "without colors",
+			useColors:    false,
+			text:         "Bold Text",
+			wantContains: "**Bold Text**",
+		},
+		{
+			name:         "with colors",
+			useColors:    true,
+			text:         "Bold Text",
+			wantContains: "Bold Text",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			formatter := &MarkdownFormatter{UseColors: tt.useColors}
+			result := formatter.formatBold(tt.text)
+
+			if !strings.Contains(result, tt.wantContains) {
+				t.Errorf("formatBold() = %q, want to contain %q", result, tt.wantContains)
+			}
+		})
+	}
+}
+
+func TestMarkdownFormatter_Colorize(t *testing.T) {
+	tests := []struct {
+		name      string
+		useColors bool
+		text      string
+		color     string
+		wantColor bool
+	}{
+		{
+			name:      "without colors",
+			useColors: false,
+			text:      "Test",
+			color:     colorRed,
+			wantColor: false,
+		},
+		{
+			name:      "with colors",
+			useColors: true,
+			text:      "Test",
+			color:     colorRed,
+			wantColor: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			formatter := &MarkdownFormatter{UseColors: tt.useColors}
+			result := formatter.colorize(tt.text, tt.color)
+
+			hasColor := strings.Contains(result, tt.color)
+			if hasColor != tt.wantColor {
+				t.Errorf("colorize() has color codes = %v, want %v", hasColor, tt.wantColor)
+			}
+
+			if !strings.Contains(result, tt.text) {
+				t.Errorf("colorize() doesn't contain original text %q", tt.text)
+			}
+		})
+	}
+}
+
+func TestMarkdownFormatter_FormatContext(t *testing.T) {
+	formatter := &MarkdownFormatter{UseColors: false}
+
+	context := map[string]interface{}{
+		"schema":     "public",
+		"table":      "users",
+		"column":     "id",
+		"pattern":    "^id_",
+		"max_length": 64,
+	}
+
+	result := formatter.formatContext(context)
+
+	// Should not include schema, table, column (they're in location)
+	if strings.Contains(result, "schema") {
+		t.Error("formatContext() should skip schema field")
+	}
+
+	if strings.Contains(result, "table=") {
+		t.Error("formatContext() should skip table field")
+	}
+
+	if strings.Contains(result, "column=") {
+		t.Error("formatContext() should skip column field")
+	}
+
+	// Should include other fields
+	if !strings.Contains(result, "pattern") {
+		t.Error("formatContext() should include pattern field")
+	}
+
+	if !strings.Contains(result, "max_length") {
+		t.Error("formatContext() should include max_length field")
+	}
+}
+
+func TestMarkdownFormatter_FormatViolation(t *testing.T) {
+	formatter := &MarkdownFormatter{UseColors: false}
+
+	violation := ValidationResult{
+		RuleName: "test_rule",
+		Level:    "error",
+		Message:  "Test violation message",
+		Location: "public.users.id",
+		Passed:   false,
+		Context: map[string]interface{}{
+			"pattern": "^id_",
+		},
+	}
+
+	result := formatter.formatViolation(violation, colorRed)
+
+	if !strings.Contains(result, "test_rule") {
+		t.Error("formatViolation() should include rule name")
+	}
+
+	if !strings.Contains(result, "Test violation message") {
+		t.Error("formatViolation() should include message")
+	}
+
+	if !strings.Contains(result, "public.users.id") {
+		t.Error("formatViolation() should include location")
+	}
+
+	if !strings.Contains(result, "Location:") {
+		t.Error("formatViolation() should include Location label")
+	}
+
+	if !strings.Contains(result, "Message:") {
+		t.Error("formatViolation() should include Message label")
+	}
+}
+
+func TestReportFormatConstants(t *testing.T) {
+	// Test that color constants are defined
+	if colorReset == "" {
+		t.Error("colorReset is not defined")
+	}
+
+	if colorRed == "" {
+		t.Error("colorRed is not defined")
+	}
+
+	if colorYellow == "" {
+		t.Error("colorYellow is not defined")
+	}
+
+	if colorGreen == "" {
+		t.Error("colorGreen is not defined")
+	}
+
+	if colorBold == "" {
+		t.Error("colorBold is not defined")
+	}
+}

pkg/inspector/rules_test.go

@@ -0,0 +1,249 @@
+package inspector
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestGetDefaultConfig(t *testing.T) {
+	config := GetDefaultConfig()
+
+	if config == nil {
+		t.Fatal("GetDefaultConfig() returned nil")
+	}
+
+	if config.Version != "1.0" {
+		t.Errorf("GetDefaultConfig() Version = %q, want \"1.0\"", config.Version)
+	}
+
+	if len(config.Rules) == 0 {
+		t.Error("GetDefaultConfig() returned no rules")
+	}
+
+	// Check that all expected rules are present
+	expectedRules := []string{
+		"primary_key_naming",
+		"primary_key_datatype",
+		"primary_key_auto_increment",
+		"foreign_key_column_naming",
+		"foreign_key_constraint_naming",
+		"foreign_key_index",
+		"table_naming_case",
+		"column_naming_case",
+		"table_name_length",
+		"column_name_length",
+		"reserved_keywords",
+		"missing_primary_key",
+		"orphaned_foreign_key",
+		"circular_dependency",
+	}
+
+	for _, ruleName := range expectedRules {
+		if _, exists := config.Rules[ruleName]; !exists {
+			t.Errorf("GetDefaultConfig() missing rule: %q", ruleName)
+		}
+	}
+}
+
+func TestLoadConfig_NonExistentFile(t *testing.T) {
+	// Try to load a non-existent file
+	config, err := LoadConfig("/path/to/nonexistent/file.yaml")
+
+	if err != nil {
+		t.Fatalf("LoadConfig() with non-existent file returned error: %v", err)
+	}
+
+	// Should return default config
+	if config == nil {
+		t.Fatal("LoadConfig() returned nil config for non-existent file")
+	}
+
+	if len(config.Rules) == 0 {
+		t.Error("LoadConfig() returned config with no rules")
+	}
+}
+
+func TestLoadConfig_ValidFile(t *testing.T) {
+	// Create a temporary config file
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "test-config.yaml")
+
+	configContent := `version: "1.0"
+rules:
+  primary_key_naming:
+    enabled: "enforce"
+    function: "primary_key_naming"
+    pattern: "^pk_"
+    message: "Primary keys must start with pk_"
+  table_name_length:
+    enabled: "warn"
+    function: "table_name_length"
+    max_length: 50
+    message: "Table name too long"
+`
+
+	err := os.WriteFile(configPath, []byte(configContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to create test config file: %v", err)
+	}
+
+	config, err := LoadConfig(configPath)
+	if err != nil {
+		t.Fatalf("LoadConfig() returned error: %v", err)
+	}
+
+	if config.Version != "1.0" {
+		t.Errorf("LoadConfig() Version = %q, want \"1.0\"", config.Version)
+	}
+
+	if len(config.Rules) != 2 {
+		t.Errorf("LoadConfig() loaded %d rules, want 2", len(config.Rules))
+	}
+
+	// Check primary_key_naming rule
+	pkRule, exists := config.Rules["primary_key_naming"]
+	if !exists {
+		t.Fatal("LoadConfig() missing primary_key_naming rule")
+	}
+
+	if pkRule.Enabled != "enforce" {
+		t.Errorf("primary_key_naming.Enabled = %q, want \"enforce\"", pkRule.Enabled)
+	}
+
+	if pkRule.Pattern != "^pk_" {
+		t.Errorf("primary_key_naming.Pattern = %q, want \"^pk_\"", pkRule.Pattern)
+	}
+
+	// Check table_name_length rule
+	lengthRule, exists := config.Rules["table_name_length"]
+	if !exists {
+		t.Fatal("LoadConfig() missing table_name_length rule")
+	}
+
+	if lengthRule.MaxLength != 50 {
+		t.Errorf("table_name_length.MaxLength = %d, want 50", lengthRule.MaxLength)
+	}
+}
+
+func TestLoadConfig_InvalidYAML(t *testing.T) {
+	// Create a temporary invalid config file
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "invalid-config.yaml")
+
+	invalidContent := `invalid: yaml: content: {[}]`
+
+	err := os.WriteFile(configPath, []byte(invalidContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to create test config file: %v", err)
+	}
+
+	_, err = LoadConfig(configPath)
+	if err == nil {
+		t.Error("LoadConfig() with invalid YAML did not return error")
+	}
+}
+
+func TestRuleIsEnabled(t *testing.T) {
+	tests := []struct {
+		name string
+		rule Rule
+		want bool
+	}{
+		{
+			name: "enforce is enabled",
+			rule: Rule{Enabled: "enforce"},
+			want: true,
+		},
+		{
+			name: "warn is enabled",
+			rule: Rule{Enabled: "warn"},
+			want: true,
+		},
+		{
+			name: "off is not enabled",
+			rule: Rule{Enabled: "off"},
+			want: false,
+		},
+		{
+			name: "empty is not enabled",
+			rule: Rule{Enabled: ""},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.rule.IsEnabled(); got != tt.want {
+				t.Errorf("Rule.IsEnabled() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRuleIsEnforced(t *testing.T) {
+	tests := []struct {
+		name string
+		rule Rule
+		want bool
+	}{
+		{
+			name: "enforce is enforced",
+			rule: Rule{Enabled: "enforce"},
+			want: true,
+		},
+		{
+			name: "warn is not enforced",
+			rule: Rule{Enabled: "warn"},
+			want: false,
+		},
+		{
+			name: "off is not enforced",
+			rule: Rule{Enabled: "off"},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.rule.IsEnforced(); got != tt.want {
+				t.Errorf("Rule.IsEnforced() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDefaultConfigRuleSettings(t *testing.T) {
+	config := GetDefaultConfig()
+
+	// Test specific rule settings
+	pkNamingRule := config.Rules["primary_key_naming"]
+	if pkNamingRule.Function != "primary_key_naming" {
+		t.Errorf("primary_key_naming.Function = %q, want \"primary_key_naming\"", pkNamingRule.Function)
+	}
+
+	if pkNamingRule.Pattern != "^id_" {
+		t.Errorf("primary_key_naming.Pattern = %q, want \"^id_\"", pkNamingRule.Pattern)
+	}
+
+	// Test datatype rule
+	pkDatatypeRule := config.Rules["primary_key_datatype"]
+	if len(pkDatatypeRule.AllowedTypes) == 0 {
+		t.Error("primary_key_datatype has no allowed types")
+	}
+
+	// Test length rule
+	tableLengthRule := config.Rules["table_name_length"]
+	if tableLengthRule.MaxLength != 64 {
+		t.Errorf("table_name_length.MaxLength = %d, want 64", tableLengthRule.MaxLength)
+	}
+
+	// Test reserved keywords rule
+	reservedRule := config.Rules["reserved_keywords"]
+	if !reservedRule.CheckTables {
+		t.Error("reserved_keywords.CheckTables should be true")
+	}
+	if !reservedRule.CheckColumns {
+		t.Error("reserved_keywords.CheckColumns should be true")
+	}
+}

pkg/inspector/validators_test.go

@@ -0,0 +1,837 @@
+package inspector
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// Helper function to create test database
+func createTestDatabase() *models.Database {
+	return &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "users",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:          "id",
+								Type:          "bigserial",
+								IsPrimaryKey:  true,
+								AutoIncrement: true,
+							},
+							"username": {
+								Name:         "username",
+								Type:         "varchar(50)",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+							"rid_organization": {
+								Name:         "rid_organization",
+								Type:         "bigint",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_users_organization": {
+								Name:              "fk_users_organization",
+								Type:              models.ForeignKeyConstraint,
+								Columns:           []string{"rid_organization"},
+								ReferencedTable:   "organizations",
+								ReferencedSchema:  "public",
+								ReferencedColumns: []string{"id"},
+							},
+						},
+						Indexes: map[string]*models.Index{
+							"idx_rid_organization": {
+								Name:    "idx_rid_organization",
+								Columns: []string{"rid_organization"},
+							},
+						},
+					},
+					{
+						Name: "organizations",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:          "id",
+								Type:          "bigserial",
+								IsPrimaryKey:  true,
+								AutoIncrement: true,
+							},
+							"name": {
+								Name:         "name",
+								Type:         "varchar(100)",
+								NotNull:      true,
+								IsPrimaryKey: false,
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func TestValidatePrimaryKeyNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern id",
+			rule: Rule{
+				Pattern: "^id$",
+				Message: "Primary key should be 'id'",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern id_",
+			rule: Rule{
+				Pattern: "^id_",
+				Message: "Primary key should start with 'id_'",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validatePrimaryKeyNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidatePrimaryKeyDatatype(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "allowed type bigserial",
+			rule: Rule{
+				AllowedTypes: []string{"bigserial", "bigint", "int"},
+				Message:      "Primary key should use integer types",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "disallowed type",
+			rule: Rule{
+				AllowedTypes: []string{"uuid"},
+				Message:      "Primary key should use UUID",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyDatatype(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyDatatype() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validatePrimaryKeyDatatype() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidatePrimaryKeyAutoIncrement(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name    string
+		rule    Rule
+		wantLen int
+	}{
+		{
+			name: "require auto increment",
+			rule: Rule{
+				RequireAutoIncrement: true,
+				Message:              "Primary key should have auto-increment",
+			},
+			wantLen: 0, // No violations - all PKs have auto-increment
+		},
+		{
+			name: "disallow auto increment",
+			rule: Rule{
+				RequireAutoIncrement: false,
+				Message:              "Primary key should not have auto-increment",
+			},
+			wantLen: 2, // 2 violations - both PKs have auto-increment
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validatePrimaryKeyAutoIncrement(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validatePrimaryKeyAutoIncrement() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyColumnNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern rid_",
+			rule: Rule{
+				Pattern: "^rid_",
+				Message: "Foreign key columns should start with 'rid_'",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern fk_",
+			rule: Rule{
+				Pattern: "^fk_",
+				Message: "Foreign key columns should start with 'fk_'",
+			},
+			wantLen:  1,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyColumnNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyColumnNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyColumnNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyConstraintNaming(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "matching pattern fk_",
+			rule: Rule{
+				Pattern: "^fk_",
+				Message: "Foreign key constraints should start with 'fk_'",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "non-matching pattern FK_",
+			rule: Rule{
+				Pattern: "^FK_",
+				Message: "Foreign key constraints should start with 'FK_'",
+			},
+			wantLen:  1,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyConstraintNaming(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyConstraintNaming() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyConstraintNaming() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateForeignKeyIndex(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "require index with index present",
+			rule: Rule{
+				RequireIndex: true,
+				Message:      "Foreign key columns should have indexes",
+			},
+			wantLen:  1,
+			wantPass: true,
+		},
+		{
+			name: "no requirement",
+			rule: Rule{
+				RequireIndex: false,
+				Message:      "Foreign key index check disabled",
+			},
+			wantLen:  0,
+			wantPass: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateForeignKeyIndex(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateForeignKeyIndex() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateForeignKeyIndex() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateTableNamingCase(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "lowercase snake_case pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-z0-9_]*$",
+				Case:    "lowercase",
+				Message: "Table names should be lowercase snake_case",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "uppercase pattern",
+			rule: Rule{
+				Pattern: "^[A-Z][A-Z0-9_]*$",
+				Case:    "uppercase",
+				Message: "Table names should be uppercase",
+			},
+			wantLen:  2,
+			wantPass: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateTableNamingCase(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateTableNamingCase() returned %d results, want %d", len(results), tt.wantLen)
+			}
+			if len(results) > 0 && results[0].Passed != tt.wantPass {
+				t.Errorf("validateTableNamingCase() passed=%v, want %v", results[0].Passed, tt.wantPass)
+			}
+		})
+	}
+}
+
+func TestValidateColumnNamingCase(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "lowercase snake_case pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-z0-9_]*$",
+				Case:    "lowercase",
+				Message: "Column names should be lowercase snake_case",
+			},
+			wantLen:  5, // 5 total columns across both tables
+			wantPass: true,
+		},
+		{
+			name: "camelCase pattern",
+			rule: Rule{
+				Pattern: "^[a-z][a-zA-Z0-9]*$",
+				Case:    "camelCase",
+				Message: "Column names should be camelCase",
+			},
+			wantLen:  5,
+			wantPass: false, // rid_organization has underscore
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateColumnNamingCase(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateColumnNamingCase() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateTableNameLength(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "max length 64",
+			rule: Rule{
+				MaxLength: 64,
+				Message:   "Table name too long",
+			},
+			wantLen:  2,
+			wantPass: true,
+		},
+		{
+			name: "max length 5",
+			rule: Rule{
+				MaxLength: 5,
+				Message:   "Table name too long",
+			},
+			wantLen:  2,
+			wantPass: false, // "users" is 5 chars (passes), "organizations" is 13 (fails)
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateTableNameLength(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateTableNameLength() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateColumnNameLength(t *testing.T) {
+	db := createTestDatabase()
+
+	tests := []struct {
+		name     string
+		rule     Rule
+		wantLen  int
+		wantPass bool
+	}{
+		{
+			name: "max length 64",
+			rule: Rule{
+				MaxLength: 64,
+				Message:   "Column name too long",
+			},
+			wantLen:  5,
+			wantPass: true,
+		},
+		{
+			name: "max length 5",
+			rule: Rule{
+				MaxLength: 5,
+				Message:   "Column name too long",
+			},
+			wantLen:  5,
+			wantPass: false, // Some columns exceed 5 chars
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateColumnNameLength(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateColumnNameLength() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateReservedKeywords(t *testing.T) {
+	// Create a database with reserved keywords
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "user", // "user" is a reserved keyword
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+							"select": { // "select" is a reserved keyword
+								Name: "select",
+								Type: "varchar(50)",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	tests := []struct {
+		name        string
+		rule        Rule
+		wantLen     int
+		checkPasses bool
+	}{
+		{
+			name: "check tables only",
+			rule: Rule{
+				CheckTables:  true,
+				CheckColumns: false,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     1, // "user" table
+			checkPasses: false,
+		},
+		{
+			name: "check columns only",
+			rule: Rule{
+				CheckTables:  false,
+				CheckColumns: true,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     2, // "id", "select" columns (id passes, select fails)
+			checkPasses: false,
+		},
+		{
+			name: "check both",
+			rule: Rule{
+				CheckTables:  true,
+				CheckColumns: true,
+				Message:      "Reserved keyword used",
+			},
+			wantLen:     3, // "user" table + "id", "select" columns
+			checkPasses: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			results := validateReservedKeywords(db, tt.rule, "test_rule")
+			if len(results) != tt.wantLen {
+				t.Errorf("validateReservedKeywords() returned %d results, want %d", len(results), tt.wantLen)
+			}
+		})
+	}
+}
+
+func TestValidateMissingPrimaryKey(t *testing.T) {
+	// Create database with and without primary keys
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "with_pk",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+						},
+					},
+					{
+						Name: "without_pk",
+						Columns: map[string]*models.Column{
+							"name": {
+								Name: "name",
+								Type: "varchar(50)",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Table missing primary key",
+	}
+
+	results := validateMissingPrimaryKey(db, rule, "test_rule")
+
+	if len(results) != 2 {
+		t.Errorf("validateMissingPrimaryKey() returned %d results, want 2", len(results))
+	}
+
+	// First result should pass (with_pk has PK)
+	if results[0].Passed != true {
+		t.Errorf("validateMissingPrimaryKey() result[0].Passed=%v, want true", results[0].Passed)
+	}
+
+	// Second result should fail (without_pk missing PK)
+	if results[1].Passed != false {
+		t.Errorf("validateMissingPrimaryKey() result[1].Passed=%v, want false", results[1].Passed)
+	}
+}
+
+func TestValidateOrphanedForeignKey(t *testing.T) {
+	// Create database with orphaned FK
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "users",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "bigint",
+								IsPrimaryKey: true,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_nonexistent": {
+								Name:             "fk_nonexistent",
+								Type:             models.ForeignKeyConstraint,
+								Columns:          []string{"rid_organization"},
+								ReferencedTable:  "nonexistent_table",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Foreign key references non-existent table",
+	}
+
+	results := validateOrphanedForeignKey(db, rule, "test_rule")
+
+	if len(results) != 1 {
+		t.Errorf("validateOrphanedForeignKey() returned %d results, want 1", len(results))
+	}
+
+	if results[0].Passed != false {
+		t.Errorf("validateOrphanedForeignKey() passed=%v, want false", results[0].Passed)
+	}
+}
+
+func TestValidateCircularDependency(t *testing.T) {
+	// Create database with circular dependency
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "table_a",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "bigint", IsPrimaryKey: true},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_to_b": {
+								Name:             "fk_to_b",
+								Type:             models.ForeignKeyConstraint,
+								ReferencedTable:  "table_b",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+					{
+						Name: "table_b",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "bigint", IsPrimaryKey: true},
+						},
+						Constraints: map[string]*models.Constraint{
+							"fk_to_a": {
+								Name:             "fk_to_a",
+								Type:             models.ForeignKeyConstraint,
+								ReferencedTable:  "table_a",
+								ReferencedSchema: "public",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	rule := Rule{
+		Message: "Circular dependency detected",
+	}
+
+	results := validateCircularDependency(db, rule, "test_rule")
+
+	// Should detect circular dependency in both tables
+	if len(results) == 0 {
+		t.Error("validateCircularDependency() returned 0 results, expected circular dependency detection")
+	}
+
+	for _, result := range results {
+		if result.Passed {
+			t.Error("validateCircularDependency() passed=true, want false for circular dependency")
+		}
+	}
+}
+
+func TestNormalizeDataType(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"varchar(50)", "varchar"},
+		{"decimal(10,2)", "decimal"},
+		{"int", "int"},
+		{"BIGINT", "bigint"},
+		{"VARCHAR(255)", "varchar"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			result := normalizeDataType(tt.input)
+			if result != tt.expected {
+				t.Errorf("normalizeDataType(%q) = %q, want %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestContains(t *testing.T) {
+	tests := []struct {
+		name     string
+		slice    []string
+		value    string
+		expected bool
+	}{
+		{"found exact", []string{"foo", "bar", "baz"}, "bar", true},
+		{"not found", []string{"foo", "bar", "baz"}, "qux", false},
+		{"case insensitive match", []string{"foo", "Bar", "baz"}, "bar", true},
+		{"empty slice", []string{}, "foo", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := contains(tt.slice, tt.value)
+			if result != tt.expected {
+				t.Errorf("contains(%v, %q) = %v, want %v", tt.slice, tt.value, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestHasCycle(t *testing.T) {
+	tests := []struct {
+		name     string
+		graph    map[string][]string
+		node     string
+		expected bool
+	}{
+		{
+			name: "simple cycle",
+			graph: map[string][]string{
+				"A": {"B"},
+				"B": {"C"},
+				"C": {"A"},
+			},
+			node:     "A",
+			expected: true,
+		},
+		{
+			name: "no cycle",
+			graph: map[string][]string{
+				"A": {"B"},
+				"B": {"C"},
+				"C": {},
+			},
+			node:     "A",
+			expected: false,
+		},
+		{
+			name: "self cycle",
+			graph: map[string][]string{
+				"A": {"A"},
+			},
+			node:     "A",
+			expected: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			visited := make(map[string]bool)
+			recStack := make(map[string]bool)
+			result := hasCycle(tt.node, tt.graph, visited, recStack)
+			if result != tt.expected {
+				t.Errorf("hasCycle() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestFormatLocation(t *testing.T) {
+	tests := []struct {
+		schema   string
+		table    string
+		column   string
+		expected string
+	}{
+		{"public", "users", "id", "public.users.id"},
+		{"public", "users", "", "public.users"},
+		{"public", "", "", "public"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.expected, func(t *testing.T) {
+			result := formatLocation(tt.schema, tt.table, tt.column)
+			if result != tt.expected {
+				t.Errorf("formatLocation(%q, %q, %q) = %q, want %q",
+					tt.schema, tt.table, tt.column, result, tt.expected)
+			}
+		})
+	}
+}

pkg/merge/merge.go

@@ -12,14 +12,16 @@ import (
 
 // MergeResult represents the result of a merge operation
 type MergeResult struct {
-	SchemasAdded   int
-	TablesAdded    int
-	ColumnsAdded   int
-	RelationsAdded int
-	DomainsAdded   int
-	EnumsAdded     int
-	ViewsAdded     int
-	SequencesAdded int
+	SchemasAdded     int
+	TablesAdded      int
+	ColumnsAdded     int
+	ConstraintsAdded int
+	IndexesAdded     int
+	RelationsAdded   int
+	DomainsAdded     int
+	EnumsAdded       int
+	ViewsAdded       int
+	SequencesAdded   int
 }
 
 // MergeOptions contains options for merge operations
@@ -120,8 +122,10 @@ func (r *MergeResult) mergeTables(schema *models.Schema, source *models.Schema,
 		}
 
 		if tgtTable, exists := existingTables[tableName]; exists {
-			// Table exists, merge its columns
+			// Table exists, merge its columns, constraints, and indexes
 			r.mergeColumns(tgtTable, srcTable)
+			r.mergeConstraints(tgtTable, srcTable)
+			r.mergeIndexes(tgtTable, srcTable)
 		} else {
 			// Table doesn't exist, add it
 			newTable := cloneTable(srcTable)
@@ -151,6 +155,52 @@ func (r *MergeResult) mergeColumns(table *models.Table, srcTable *models.Table)
 	}
 }
 
+func (r *MergeResult) mergeConstraints(table *models.Table, srcTable *models.Table) {
+	// Initialize constraints map if nil
+	if table.Constraints == nil {
+		table.Constraints = make(map[string]*models.Constraint)
+	}
+
+	// Create map of existing constraints
+	existingConstraints := make(map[string]*models.Constraint)
+	for constName := range table.Constraints {
+		existingConstraints[constName] = table.Constraints[constName]
+	}
+
+	// Merge constraints
+	for constName, srcConst := range srcTable.Constraints {
+		if _, exists := existingConstraints[constName]; !exists {
+			// Constraint doesn't exist, add it
+			newConst := cloneConstraint(srcConst)
+			table.Constraints[constName] = newConst
+			r.ConstraintsAdded++
+		}
+	}
+}
+
+func (r *MergeResult) mergeIndexes(table *models.Table, srcTable *models.Table) {
+	// Initialize indexes map if nil
+	if table.Indexes == nil {
+		table.Indexes = make(map[string]*models.Index)
+	}
+
+	// Create map of existing indexes
+	existingIndexes := make(map[string]*models.Index)
+	for idxName := range table.Indexes {
+		existingIndexes[idxName] = table.Indexes[idxName]
+	}
+
+	// Merge indexes
+	for idxName, srcIdx := range srcTable.Indexes {
+		if _, exists := existingIndexes[idxName]; !exists {
+			// Index doesn't exist, add it
+			newIdx := cloneIndex(srcIdx)
+			table.Indexes[idxName] = newIdx
+			r.IndexesAdded++
+		}
+	}
+}
+
 func (r *MergeResult) mergeViews(schema *models.Schema, source *models.Schema) {
 	// Create map of existing views
 	existingViews := make(map[string]*models.View)
@@ -552,6 +602,8 @@ func GetMergeSummary(result *MergeResult) string {
 		fmt.Sprintf("Schemas added:     %d", result.SchemasAdded),
 		fmt.Sprintf("Tables added:      %d", result.TablesAdded),
 		fmt.Sprintf("Columns added:     %d", result.ColumnsAdded),
+		fmt.Sprintf("Constraints added: %d", result.ConstraintsAdded),
+		fmt.Sprintf("Indexes added:     %d", result.IndexesAdded),
 		fmt.Sprintf("Views added:       %d", result.ViewsAdded),
 		fmt.Sprintf("Sequences added:   %d", result.SequencesAdded),
 		fmt.Sprintf("Enums added:       %d", result.EnumsAdded),
@@ -560,6 +612,7 @@ func GetMergeSummary(result *MergeResult) string {
 	}
 
 	totalAdded := result.SchemasAdded + result.TablesAdded + result.ColumnsAdded +
+		result.ConstraintsAdded + result.IndexesAdded +
 		result.ViewsAdded + result.SequencesAdded + result.EnumsAdded +
 		result.RelationsAdded + result.DomainsAdded
 

pkg/merge/merge_test.go

@@ -0,0 +1,617 @@
+package merge
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestMergeDatabases_NilInputs(t *testing.T) {
+	result := MergeDatabases(nil, nil, nil)
+	if result == nil {
+		t.Fatal("Expected non-nil result")
+	}
+	if result.SchemasAdded != 0 {
+		t.Errorf("Expected 0 schemas added, got %d", result.SchemasAdded)
+	}
+}
+
+func TestMergeDatabases_NewSchema(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "auth"},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.SchemasAdded != 1 {
+		t.Errorf("Expected 1 schema added, got %d", result.SchemasAdded)
+	}
+	if len(target.Schemas) != 2 {
+		t.Errorf("Expected 2 schemas in target, got %d", len(target.Schemas))
+	}
+}
+
+func TestMergeDatabases_ExistingSchema(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{Name: "public"},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.SchemasAdded != 0 {
+		t.Errorf("Expected 0 schemas added, got %d", result.SchemasAdded)
+	}
+	if len(target.Schemas) != 1 {
+		t.Errorf("Expected 1 schema in target, got %d", len(target.Schemas))
+	}
+}
+
+func TestMergeTables_NewTable(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "posts",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.TablesAdded != 1 {
+		t.Errorf("Expected 1 table added, got %d", result.TablesAdded)
+	}
+	if len(target.Schemas[0].Tables) != 2 {
+		t.Errorf("Expected 2 tables in target schema, got %d", len(target.Schemas[0].Tables))
+	}
+}
+
+func TestMergeColumns_NewColumn(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "int"},
+						},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"email": {Name: "email", Type: "varchar"},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ColumnsAdded != 1 {
+		t.Errorf("Expected 1 column added, got %d", result.ColumnsAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Columns) != 2 {
+		t.Errorf("Expected 2 columns in target table, got %d", len(target.Schemas[0].Tables[0].Columns))
+	}
+}
+
+func TestMergeConstraints_NewConstraint(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:        "users",
+						Schema:      "public",
+						Columns:     map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ConstraintsAdded != 1 {
+		t.Errorf("Expected 1 constraint added, got %d", result.ConstraintsAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Constraints) != 1 {
+		t.Errorf("Expected 1 constraint in target table, got %d", len(target.Schemas[0].Tables[0].Constraints))
+	}
+}
+
+func TestMergeConstraints_NilConstraintsMap(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:        "users",
+						Schema:      "public",
+						Columns:     map[string]*models.Column{},
+						Constraints: nil, // Nil map
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ConstraintsAdded != 1 {
+		t.Errorf("Expected 1 constraint added, got %d", result.ConstraintsAdded)
+	}
+	if target.Schemas[0].Tables[0].Constraints == nil {
+		t.Error("Expected constraints map to be initialized")
+	}
+	if len(target.Schemas[0].Tables[0].Constraints) != 1 {
+		t.Errorf("Expected 1 constraint in target table, got %d", len(target.Schemas[0].Tables[0].Constraints))
+	}
+}
+
+func TestMergeIndexes_NewIndex(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+	if len(target.Schemas[0].Tables[0].Indexes) != 1 {
+		t.Errorf("Expected 1 index in target table, got %d", len(target.Schemas[0].Tables[0].Indexes))
+	}
+}
+
+func TestMergeIndexes_NilIndexesMap(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: nil, // Nil map
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+	if target.Schemas[0].Tables[0].Indexes == nil {
+		t.Error("Expected indexes map to be initialized")
+	}
+	if len(target.Schemas[0].Tables[0].Indexes) != 1 {
+		t.Errorf("Expected 1 index in target table, got %d", len(target.Schemas[0].Tables[0].Indexes))
+	}
+}
+
+func TestMergeOptions_SkipTableNames(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "users",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:    "migrations",
+						Schema:  "public",
+						Columns: map[string]*models.Column{},
+					},
+				},
+			},
+		},
+	}
+
+	opts := &MergeOptions{
+		SkipTableNames: map[string]bool{
+			"migrations": true,
+		},
+	}
+
+	result := MergeDatabases(target, source, opts)
+	if result.TablesAdded != 0 {
+		t.Errorf("Expected 0 tables added (skipped), got %d", result.TablesAdded)
+	}
+	if len(target.Schemas[0].Tables) != 1 {
+		t.Errorf("Expected 1 table in target schema, got %d", len(target.Schemas[0].Tables))
+	}
+}
+
+func TestMergeViews_NewView(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:  "public",
+				Views: []*models.View{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Views: []*models.View{
+					{
+						Name:       "user_summary",
+						Schema:     "public",
+						Definition: "SELECT * FROM users",
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.ViewsAdded != 1 {
+		t.Errorf("Expected 1 view added, got %d", result.ViewsAdded)
+	}
+	if len(target.Schemas[0].Views) != 1 {
+		t.Errorf("Expected 1 view in target schema, got %d", len(target.Schemas[0].Views))
+	}
+}
+
+func TestMergeEnums_NewEnum(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:  "public",
+				Enums: []*models.Enum{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Enums: []*models.Enum{
+					{
+						Name:   "user_role",
+						Schema: "public",
+						Values: []string{"admin", "user"},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.EnumsAdded != 1 {
+		t.Errorf("Expected 1 enum added, got %d", result.EnumsAdded)
+	}
+	if len(target.Schemas[0].Enums) != 1 {
+		t.Errorf("Expected 1 enum in target schema, got %d", len(target.Schemas[0].Enums))
+	}
+}
+
+func TestMergeDomains_NewDomain(t *testing.T) {
+	target := &models.Database{
+		Domains: []*models.Domain{},
+	}
+	source := &models.Database{
+		Domains: []*models.Domain{
+			{
+				Name:        "auth",
+				Description: "Authentication domain",
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.DomainsAdded != 1 {
+		t.Errorf("Expected 1 domain added, got %d", result.DomainsAdded)
+	}
+	if len(target.Domains) != 1 {
+		t.Errorf("Expected 1 domain in target, got %d", len(target.Domains))
+	}
+}
+
+func TestMergeRelations_NewRelation(t *testing.T) {
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name:      "public",
+				Relations: []*models.Relationship{},
+			},
+		},
+	}
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Relations: []*models.Relationship{
+					{
+						Name:        "fk_posts_user",
+						Type:        models.OneToMany,
+						FromTable:   "posts",
+						FromColumns: []string{"user_id"},
+						ToTable:     "users",
+						ToColumns:   []string{"id"},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+	if result.RelationsAdded != 1 {
+		t.Errorf("Expected 1 relation added, got %d", result.RelationsAdded)
+	}
+	if len(target.Schemas[0].Relations) != 1 {
+		t.Errorf("Expected 1 relation in target schema, got %d", len(target.Schemas[0].Relations))
+	}
+}
+
+func TestGetMergeSummary(t *testing.T) {
+	result := &MergeResult{
+		SchemasAdded:     1,
+		TablesAdded:      2,
+		ColumnsAdded:     5,
+		ConstraintsAdded: 3,
+		IndexesAdded:     2,
+		ViewsAdded:       1,
+	}
+
+	summary := GetMergeSummary(result)
+	if summary == "" {
+		t.Error("Expected non-empty summary")
+	}
+	if len(summary) < 50 {
+		t.Errorf("Summary seems too short: %s", summary)
+	}
+}
+
+func TestGetMergeSummary_Nil(t *testing.T) {
+	summary := GetMergeSummary(nil)
+	if summary == "" {
+		t.Error("Expected non-empty summary for nil result")
+	}
+}
+
+func TestComplexMerge(t *testing.T) {
+	// Target with existing structure
+	target := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"id": {Name: "id", Type: "int"},
+						},
+						Constraints: map[string]*models.Constraint{},
+						Indexes:     map[string]*models.Index{},
+					},
+				},
+			},
+		},
+	}
+
+	// Source with new columns, constraints, and indexes
+	source := &models.Database{
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name:   "users",
+						Schema: "public",
+						Columns: map[string]*models.Column{
+							"email": {Name: "email", Type: "varchar"},
+							"guid":  {Name: "guid", Type: "uuid"},
+						},
+						Constraints: map[string]*models.Constraint{
+							"ukey_users_email": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"email"},
+								Name:    "ukey_users_email",
+							},
+							"ukey_users_guid": {
+								Type:    models.UniqueConstraint,
+								Columns: []string{"guid"},
+								Name:    "ukey_users_guid",
+							},
+						},
+						Indexes: map[string]*models.Index{
+							"idx_users_email": {
+								Name:    "idx_users_email",
+								Columns: []string{"email"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	result := MergeDatabases(target, source, nil)
+
+	// Verify counts
+	if result.ColumnsAdded != 2 {
+		t.Errorf("Expected 2 columns added, got %d", result.ColumnsAdded)
+	}
+	if result.ConstraintsAdded != 2 {
+		t.Errorf("Expected 2 constraints added, got %d", result.ConstraintsAdded)
+	}
+	if result.IndexesAdded != 1 {
+		t.Errorf("Expected 1 index added, got %d", result.IndexesAdded)
+	}
+
+	// Verify target has merged data
+	table := target.Schemas[0].Tables[0]
+	if len(table.Columns) != 3 {
+		t.Errorf("Expected 3 columns in merged table, got %d", len(table.Columns))
+	}
+	if len(table.Constraints) != 2 {
+		t.Errorf("Expected 2 constraints in merged table, got %d", len(table.Constraints))
+	}
+	if len(table.Indexes) != 1 {
+		t.Errorf("Expected 1 index in merged table, got %d", len(table.Indexes))
+	}
+
+	// Verify specific constraint
+	if _, exists := table.Constraints["ukey_users_guid"]; !exists {
+		t.Error("Expected ukey_users_guid constraint to exist")
+	}
+}

pkg/pgsql/datatypes_test.go

@@ -0,0 +1,339 @@
+package pgsql
+
+import (
+	"testing"
+)
+
+func TestValidSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		sqltype string
+		want    bool
+	}{
+		// PostgreSQL types
+		{"Valid PGSQL bigint", "bigint", true},
+		{"Valid PGSQL integer", "integer", true},
+		{"Valid PGSQL text", "text", true},
+		{"Valid PGSQL boolean", "boolean", true},
+		{"Valid PGSQL double precision", "double precision", true},
+		{"Valid PGSQL bytea", "bytea", true},
+		{"Valid PGSQL uuid", "uuid", true},
+		{"Valid PGSQL jsonb", "jsonb", true},
+		{"Valid PGSQL json", "json", true},
+		{"Valid PGSQL timestamp", "timestamp", true},
+		{"Valid PGSQL date", "date", true},
+		{"Valid PGSQL time", "time", true},
+		{"Valid PGSQL citext", "citext", true},
+
+		// Standard types
+		{"Valid std double", "double", true},
+		{"Valid std blob", "blob", true},
+
+		// Case insensitive
+		{"Case insensitive BIGINT", "BIGINT", true},
+		{"Case insensitive TeXt", "TeXt", true},
+		{"Case insensitive BoOlEaN", "BoOlEaN", true},
+
+		// Invalid types
+		{"Invalid type", "invalidtype", false},
+		{"Invalid type varchar", "varchar", false},
+		{"Empty string", "", false},
+		{"Random string", "foobar", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ValidSQLType(tt.sqltype)
+			if got != tt.want {
+				t.Errorf("ValidSQLType(%q) = %v, want %v", tt.sqltype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		anytype string
+		want    string
+	}{
+		// Go types to PostgreSQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double precision", "float64", "double precision"},
+		{"Go float32 to real", "float32", "real"},
+		{"Go []byte to bytea", "[]byte", "bytea"},
+
+		// SQL types remain SQL types
+		{"SQL bigint", "bigint", "bigint"},
+		{"SQL integer", "integer", "integer"},
+		{"SQL text", "text", "text"},
+		{"SQL boolean", "boolean", "boolean"},
+		{"SQL uuid", "uuid", "uuid"},
+		{"SQL jsonb", "jsonb", "jsonb"},
+
+		// Case insensitive Go types
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+		{"Case insensitive STRING", "STRING", "text"},
+
+		// Case insensitive SQL types
+		{"Case insensitive BIGINT", "BIGINT", "bigint"},
+		{"Case insensitive TEXT", "TEXT", "text"},
+
+		// Custom types
+		{"Custom sqluuid", "sqluuid", "uuid"},
+		{"Custom sqljsonb", "sqljsonb", "jsonb"},
+		{"Custom sqlint64", "sqlint64", "bigint"},
+
+		// Unknown types default to text
+		{"Unknown type varchar", "varchar", "text"},
+		{"Unknown type foobar", "foobar", "text"},
+		{"Empty string", "", "text"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetSQLType(tt.anytype)
+			if got != tt.want {
+				t.Errorf("GetSQLType(%q) = %q, want %q", tt.anytype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestConvertSQLType(t *testing.T) {
+	tests := []struct {
+		name    string
+		anytype string
+		want    string
+	}{
+		// Go types to PostgreSQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double precision", "float64", "double precision"},
+		{"Go float32 to real", "float32", "real"},
+		{"Go []byte to bytea", "[]byte", "bytea"},
+
+		// SQL types remain SQL types
+		{"SQL bigint", "bigint", "bigint"},
+		{"SQL integer", "integer", "integer"},
+		{"SQL text", "text", "text"},
+		{"SQL boolean", "boolean", "boolean"},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+
+		// Unknown types remain unchanged (difference from GetSQLType)
+		{"Unknown type varchar", "varchar", "varchar"},
+		{"Unknown type foobar", "foobar", "foobar"},
+		{"Empty string", "", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ConvertSQLType(tt.anytype)
+			if got != tt.want {
+				t.Errorf("ConvertSQLType(%q) = %q, want %q", tt.anytype, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsGoType(t *testing.T) {
+	tests := []struct {
+		name     string
+		typeName string
+		want     bool
+	}{
+		// Go basic types
+		{"Go bool", "bool", true},
+		{"Go int64", "int64", true},
+		{"Go int", "int", true},
+		{"Go int32", "int32", true},
+		{"Go int16", "int16", true},
+		{"Go int8", "int8", true},
+		{"Go uint", "uint", true},
+		{"Go uint64", "uint64", true},
+		{"Go uint32", "uint32", true},
+		{"Go uint16", "uint16", true},
+		{"Go uint8", "uint8", true},
+		{"Go float64", "float64", true},
+		{"Go float32", "float32", true},
+		{"Go string", "string", true},
+		{"Go []byte", "[]byte", true},
+
+		// Go custom types
+		{"Go complex64", "complex64", true},
+		{"Go complex128", "complex128", true},
+		{"Go uintptr", "uintptr", true},
+		{"Go Pointer", "Pointer", true},
+
+		// Custom SQL types
+		{"Custom sqluuid", "sqluuid", true},
+		{"Custom sqljsonb", "sqljsonb", true},
+		{"Custom sqlint64", "sqlint64", true},
+		{"Custom customdate", "customdate", true},
+		{"Custom customtime", "customtime", true},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", true},
+		{"Case insensitive InT64", "InT64", true},
+		{"Case insensitive STRING", "STRING", true},
+
+		// SQL types (not Go types)
+		{"SQL bigint", "bigint", false},
+		{"SQL integer", "integer", false},
+		{"SQL text", "text", false},
+		{"SQL boolean", "boolean", false},
+
+		// Invalid types
+		{"Invalid type", "invalidtype", false},
+		{"Empty string", "", false},
+		{"Random string", "foobar", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsGoType(tt.typeName)
+			if got != tt.want {
+				t.Errorf("IsGoType(%q) = %v, want %v", tt.typeName, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetStdTypeFromGo(t *testing.T) {
+	tests := []struct {
+		name     string
+		typeName string
+		want     string
+	}{
+		// Go types to standard SQL types
+		{"Go bool to boolean", "bool", "boolean"},
+		{"Go int64 to bigint", "int64", "bigint"},
+		{"Go int to integer", "int", "integer"},
+		{"Go string to text", "string", "text"},
+		{"Go float64 to double", "float64", "double"},
+		{"Go float32 to double", "float32", "double"},
+		{"Go []byte to blob", "[]byte", "blob"},
+		{"Go int32 to integer", "int32", "integer"},
+		{"Go int16 to smallint", "int16", "smallint"},
+
+		// Custom types
+		{"Custom sqluuid to uuid", "sqluuid", "uuid"},
+		{"Custom sqljsonb to jsonb", "sqljsonb", "jsonb"},
+		{"Custom sqlint64 to bigint", "sqlint64", "bigint"},
+		{"Custom customdate to date", "customdate", "date"},
+
+		// Case insensitive
+		{"Case insensitive BOOL", "BOOL", "boolean"},
+		{"Case insensitive InT64", "InT64", "bigint"},
+		{"Case insensitive STRING", "STRING", "text"},
+
+		// Non-Go types remain unchanged
+		{"SQL bigint unchanged", "bigint", "bigint"},
+		{"SQL integer unchanged", "integer", "integer"},
+		{"Invalid type unchanged", "invalidtype", "invalidtype"},
+		{"Empty string unchanged", "", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetStdTypeFromGo(tt.typeName)
+			if got != tt.want {
+				t.Errorf("GetStdTypeFromGo(%q) = %q, want %q", tt.typeName, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGoToStdTypesMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"bool":    "boolean",
+		"int64":   "bigint",
+		"int":     "integer",
+		"string":  "text",
+		"float64": "double",
+		"[]byte":  "blob",
+	}
+
+	for goType, expectedStd := range expectedMappings {
+		if stdType, ok := GoToStdTypes[goType]; !ok {
+			t.Errorf("GoToStdTypes missing entry for %q", goType)
+		} else if stdType != expectedStd {
+			t.Errorf("GoToStdTypes[%q] = %q, want %q", goType, stdType, expectedStd)
+		}
+	}
+
+	// Test that the map is not empty
+	if len(GoToStdTypes) == 0 {
+		t.Error("GoToStdTypes map is empty")
+	}
+}
+
+func TestGoToPGSQLTypesMap(t *testing.T) {
+	// Test that the map contains expected entries
+	expectedMappings := map[string]string{
+		"bool":    "boolean",
+		"int64":   "bigint",
+		"int":     "integer",
+		"string":  "text",
+		"float64": "double precision",
+		"float32": "real",
+		"[]byte":  "bytea",
+	}
+
+	for goType, expectedPG := range expectedMappings {
+		if pgType, ok := GoToPGSQLTypes[goType]; !ok {
+			t.Errorf("GoToPGSQLTypes missing entry for %q", goType)
+		} else if pgType != expectedPG {
+			t.Errorf("GoToPGSQLTypes[%q] = %q, want %q", goType, pgType, expectedPG)
+		}
+	}
+
+	// Test that the map is not empty
+	if len(GoToPGSQLTypes) == 0 {
+		t.Error("GoToPGSQLTypes map is empty")
+	}
+}
+
+func TestTypeConversionConsistency(t *testing.T) {
+	// Test that GetSQLType and ConvertSQLType are consistent for known types
+	knownGoTypes := []string{"bool", "int64", "int", "string", "float64", "[]byte"}
+
+	for _, goType := range knownGoTypes {
+		getSQLResult := GetSQLType(goType)
+		convertResult := ConvertSQLType(goType)
+
+		if getSQLResult != convertResult {
+			t.Errorf("Inconsistent results for %q: GetSQLType=%q, ConvertSQLType=%q",
+				goType, getSQLResult, convertResult)
+		}
+	}
+}
+
+func TestGetSQLTypeVsConvertSQLTypeDifference(t *testing.T) {
+	// Test that GetSQLType returns "text" for unknown types
+	// while ConvertSQLType returns the input unchanged
+	unknownTypes := []string{"varchar", "char", "customtype", "unknowntype"}
+
+	for _, unknown := range unknownTypes {
+		getSQLResult := GetSQLType(unknown)
+		convertResult := ConvertSQLType(unknown)
+
+		if getSQLResult != "text" {
+			t.Errorf("GetSQLType(%q) = %q, want %q", unknown, getSQLResult, "text")
+		}
+
+		if convertResult != unknown {
+			t.Errorf("ConvertSQLType(%q) = %q, want %q", unknown, convertResult, unknown)
+		}
+	}
+}

pkg/pgsql/doc.go

@@ -0,0 +1,36 @@
+// Package pgsql provides PostgreSQL-specific utilities and helpers.
+//
+// # Overview
+//
+// The pgsql package contains PostgreSQL-specific functionality including:
+//   - SQL reserved keyword validation
+//   - Data type mappings and conversions
+//   - PostgreSQL-specific schema introspection helpers
+//
+// # Components
+//
+// keywords.go - SQL reserved keywords validation
+//
+//	Provides functions to check if identifiers conflict with SQL reserved words
+//	and need quoting for safe usage in PostgreSQL queries.
+//
+// datatypes.go - PostgreSQL data type utilities
+//
+//	Contains mappings between PostgreSQL data types and their equivalents in other
+//	systems, as well as type conversion and normalization functions.
+//
+// # Usage
+//
+//	// Check if identifier needs quoting
+//	if pgsql.IsReservedKeyword("user") {
+//	    // Quote the identifier
+//	}
+//
+//	// Normalize data type
+//	normalizedType := pgsql.NormalizeDataType("varchar(255)")
+//
+// # Purpose
+//
+// This package supports the PostgreSQL reader and writer implementations by providing
+// shared utilities for handling PostgreSQL-specific schema elements and constraints.
+package pgsql

pkg/pgsql/keywords_test.go

@@ -0,0 +1,136 @@
+package pgsql
+
+import (
+	"testing"
+)
+
+func TestGetPostgresKeywords(t *testing.T) {
+	keywords := GetPostgresKeywords()
+
+	// Test that keywords are returned
+	if len(keywords) == 0 {
+		t.Fatal("Expected non-empty list of keywords")
+	}
+
+	// Test that we get all keywords from the map
+	expectedCount := len(postgresKeywords)
+	if len(keywords) != expectedCount {
+		t.Errorf("Expected %d keywords, got %d", expectedCount, len(keywords))
+	}
+
+	// Test that all returned keywords exist in the map
+	for _, keyword := range keywords {
+		if !postgresKeywords[keyword] {
+			t.Errorf("Keyword %q not found in postgresKeywords map", keyword)
+		}
+	}
+
+	// Test that no duplicate keywords are returned
+	seen := make(map[string]bool)
+	for _, keyword := range keywords {
+		if seen[keyword] {
+			t.Errorf("Duplicate keyword found: %q", keyword)
+		}
+		seen[keyword] = true
+	}
+}
+
+func TestPostgresKeywordsMap(t *testing.T) {
+	tests := []struct {
+		name    string
+		keyword string
+		want    bool
+	}{
+		{"SELECT keyword", "select", true},
+		{"FROM keyword", "from", true},
+		{"WHERE keyword", "where", true},
+		{"TABLE keyword", "table", true},
+		{"PRIMARY keyword", "primary", true},
+		{"FOREIGN keyword", "foreign", true},
+		{"CREATE keyword", "create", true},
+		{"DROP keyword", "drop", true},
+		{"ALTER keyword", "alter", true},
+		{"INDEX keyword", "index", true},
+		{"NOT keyword", "not", true},
+		{"NULL keyword", "null", true},
+		{"TRUE keyword", "true", true},
+		{"FALSE keyword", "false", true},
+		{"Non-keyword lowercase", "notakeyword", false},
+		{"Non-keyword uppercase", "NOTAKEYWORD", false},
+		{"Empty string", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := postgresKeywords[tt.keyword]
+			if got != tt.want {
+				t.Errorf("postgresKeywords[%q] = %v, want %v", tt.keyword, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestPostgresKeywordsMapContent(t *testing.T) {
+	// Test that the map contains expected common keywords
+	commonKeywords := []string{
+		"select", "insert", "update", "delete", "create", "drop", "alter",
+		"table", "index", "view", "schema", "function", "procedure",
+		"primary", "foreign", "key", "constraint", "unique", "check",
+		"null", "not", "and", "or", "like", "in", "between",
+		"join", "inner", "left", "right", "cross", "full", "outer",
+		"where", "having", "group", "order", "limit", "offset",
+		"union", "intersect", "except",
+		"begin", "commit", "rollback", "transaction",
+	}
+
+	for _, keyword := range commonKeywords {
+		if !postgresKeywords[keyword] {
+			t.Errorf("Expected common keyword %q to be in postgresKeywords map", keyword)
+		}
+	}
+}
+
+func TestPostgresKeywordsMapSize(t *testing.T) {
+	// PostgreSQL has a substantial list of reserved keywords
+	// This test ensures the map has a reasonable number of entries
+	minExpectedKeywords := 200 // PostgreSQL 13+ has 400+ reserved words
+
+	if len(postgresKeywords) < minExpectedKeywords {
+		t.Errorf("Expected at least %d keywords, got %d. The map may be incomplete.",
+			minExpectedKeywords, len(postgresKeywords))
+	}
+}
+
+func TestGetPostgresKeywordsConsistency(t *testing.T) {
+	// Test that calling GetPostgresKeywords multiple times returns consistent results
+	keywords1 := GetPostgresKeywords()
+	keywords2 := GetPostgresKeywords()
+
+	if len(keywords1) != len(keywords2) {
+		t.Errorf("Inconsistent results: first call returned %d keywords, second call returned %d",
+			len(keywords1), len(keywords2))
+	}
+
+	// Create a map from both results to compare
+	map1 := make(map[string]bool)
+	map2 := make(map[string]bool)
+
+	for _, k := range keywords1 {
+		map1[k] = true
+	}
+	for _, k := range keywords2 {
+		map2[k] = true
+	}
+
+	// Check that both contain the same keywords
+	for k := range map1 {
+		if !map2[k] {
+			t.Errorf("Keyword %q present in first call but not in second", k)
+		}
+	}
+	for k := range map2 {
+		if !map1[k] {
+			t.Errorf("Keyword %q present in second call but not in first", k)
+		}
+	}
+}

pkg/readers/dbml/reader.go

@@ -128,6 +128,46 @@ func (r *Reader) readDirectoryDBML(dirPath string) (*models.Database, error) {
 	return db, nil
 }
 
+// splitIdentifier splits a dotted identifier while respecting quotes
+// Handles cases like: "schema.with.dots"."table"."column"
+func splitIdentifier(s string) []string {
+	var parts []string
+	var current strings.Builder
+	inQuote := false
+	quoteChar := byte(0)
+
+	for i := 0; i < len(s); i++ {
+		ch := s[i]
+
+		if !inQuote {
+			switch ch {
+			case '"', '\'':
+				inQuote = true
+				quoteChar = ch
+				current.WriteByte(ch)
+			case '.':
+				if current.Len() > 0 {
+					parts = append(parts, current.String())
+					current.Reset()
+				}
+			default:
+				current.WriteByte(ch)
+			}
+		} else {
+			current.WriteByte(ch)
+			if ch == quoteChar {
+				inQuote = false
+			}
+		}
+	}
+
+	if current.Len() > 0 {
+		parts = append(parts, current.String())
+	}
+
+	return parts
+}
+
 // stripQuotes removes surrounding quotes and comments from an identifier
 func stripQuotes(s string) string {
 	s = strings.TrimSpace(s)
@@ -409,7 +449,9 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 		// Parse Table definition
 		if matches := tableRegex.FindStringSubmatch(line); matches != nil {
 			tableName := matches[1]
-			parts := strings.Split(tableName, ".")
+			// Strip comments/notes before parsing to avoid dots in notes
+			tableName = strings.TrimSpace(regexp.MustCompile(`\s*\[.*?\]\s*`).ReplaceAllString(tableName, ""))
+			parts := splitIdentifier(tableName)
 
 			if len(parts) == 2 {
 				currentSchema = stripQuotes(parts[0])
@@ -561,8 +603,10 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 					column.Default = strings.Trim(defaultVal, "'\"")
 				} else if attr == "unique" {
 					// Create a unique constraint
+					// Clean table name by removing leading underscores to avoid double underscores
+					cleanTableName := strings.TrimLeft(tableName, "_")
 					uniqueConstraint := models.InitConstraint(
-						fmt.Sprintf("uq_%s", columnName),
+						fmt.Sprintf("ukey_%s_%s", cleanTableName, columnName),
 						models.UniqueConstraint,
 					)
 					uniqueConstraint.Schema = schemaName
@@ -610,8 +654,8 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 							constraint.Table = tableName
 							constraint.Columns = []string{columnName}
 						}
-						// Generate short constraint name based on the column
-						constraint.Name = fmt.Sprintf("fk_%s", constraint.Columns[0])
+						// Generate constraint name based on table and columns
+						constraint.Name = fmt.Sprintf("fk_%s_%s", constraint.Table, strings.Join(constraint.Columns, "_"))
 					}
 				}
 			}
@@ -695,7 +739,11 @@ func (r *Reader) parseIndex(line, tableName, schemaName string) *models.Index {
 
 	// Generate name if not provided
 	if index.Name == "" {
-		index.Name = fmt.Sprintf("idx_%s_%s", tableName, strings.Join(columns, "_"))
+		prefix := "idx"
+		if index.Unique {
+			prefix = "uidx"
+		}
+		index.Name = fmt.Sprintf("%s_%s_%s", prefix, tableName, strings.Join(columns, "_"))
 	}
 
 	return index
@@ -755,10 +803,10 @@ func (r *Reader) parseRef(refStr string) *models.Constraint {
 		return nil
 	}
 
-	// Generate short constraint name based on the source column
-	constraintName := fmt.Sprintf("fk_%s_%s", fromTable, toTable)
-	if len(fromColumns) > 0 {
-		constraintName = fmt.Sprintf("fk_%s", fromColumns[0])
+	// Generate constraint name based on table and columns
+	constraintName := fmt.Sprintf("fk_%s_%s", fromTable, strings.Join(fromColumns, "_"))
+	if len(fromColumns) == 0 {
+		constraintName = fmt.Sprintf("fk_%s_%s", fromTable, toTable)
 	}
 
 	constraint := models.InitConstraint(
@@ -814,7 +862,7 @@ func (r *Reader) parseTableRef(ref string) (schema, table string, columns []stri
 	}
 
 	// Parse schema, table, and optionally column
-	parts := strings.Split(strings.TrimSpace(ref), ".")
+	parts := splitIdentifier(strings.TrimSpace(ref))
 	if len(parts) == 3 {
 		// Format: "schema"."table"."column"
 		schema = stripQuotes(parts[0])

pkg/readers/dbml/reader_test.go

@@ -777,6 +777,76 @@ func TestParseFilePrefix(t *testing.T) {
 	}
 }
 
+func TestConstraintNaming(t *testing.T) {
+	// Test that constraints are named with proper prefixes
+	opts := &readers.ReaderOptions{
+		FilePath: filepath.Join("..", "..", "..", "tests", "assets", "dbml", "complex.dbml"),
+	}
+
+	reader := NewReader(opts)
+	db, err := reader.ReadDatabase()
+	if err != nil {
+		t.Fatalf("ReadDatabase() error = %v", err)
+	}
+
+	// Find users table
+	var usersTable *models.Table
+	var postsTable *models.Table
+	for _, schema := range db.Schemas {
+		for _, table := range schema.Tables {
+			if table.Name == "users" {
+				usersTable = table
+			} else if table.Name == "posts" {
+				postsTable = table
+			}
+		}
+	}
+
+	if usersTable == nil {
+		t.Fatal("Users table not found")
+	}
+	if postsTable == nil {
+		t.Fatal("Posts table not found")
+	}
+
+	// Test unique constraint naming: ukey_table_column
+	if _, exists := usersTable.Constraints["ukey_users_email"]; !exists {
+		t.Error("Expected unique constraint 'ukey_users_email' not found")
+		t.Logf("Available constraints: %v", getKeys(usersTable.Constraints))
+	}
+
+	if _, exists := postsTable.Constraints["ukey_posts_slug"]; !exists {
+		t.Error("Expected unique constraint 'ukey_posts_slug' not found")
+		t.Logf("Available constraints: %v", getKeys(postsTable.Constraints))
+	}
+
+	// Test foreign key naming: fk_table_column
+	if _, exists := postsTable.Constraints["fk_posts_user_id"]; !exists {
+		t.Error("Expected foreign key 'fk_posts_user_id' not found")
+		t.Logf("Available constraints: %v", getKeys(postsTable.Constraints))
+	}
+
+	// Test unique index naming: uidx_table_columns
+	if _, exists := postsTable.Indexes["uidx_posts_slug"]; !exists {
+		t.Error("Expected unique index 'uidx_posts_slug' not found")
+		t.Logf("Available indexes: %v", getKeys(postsTable.Indexes))
+	}
+
+	// Test regular index naming: idx_table_columns
+	if _, exists := postsTable.Indexes["idx_posts_user_id_published"]; !exists {
+		t.Error("Expected index 'idx_posts_user_id_published' not found")
+		t.Logf("Available indexes: %v", getKeys(postsTable.Indexes))
+	}
+}
+
+func getKeys[V any](m map[string]V) []string {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
 func TestHasCommentedRefs(t *testing.T) {
 	// Test with the actual multifile test fixtures
 	tests := []struct {

pkg/readers/doc.go

@@ -0,0 +1,53 @@
+// Package readers provides interfaces and implementations for reading database schemas
+// from various input formats and data sources.
+//
+// # Overview
+//
+// The readers package defines a common Reader interface that all format-specific readers
+// implement. This allows RelSpec to read database schemas from multiple sources including:
+//   - Live databases (PostgreSQL, SQLite)
+//   - Schema definition files (DBML, DCTX, DrawDB, GraphQL)
+//   - ORM model files (GORM, Bun, Drizzle, Prisma, TypeORM)
+//   - Data interchange formats (JSON, YAML)
+//
+// # Architecture
+//
+// Each reader implementation is located in its own subpackage (e.g., pkg/readers/dbml,
+// pkg/readers/pgsql) and implements the Reader interface, supporting three levels of
+// granularity:
+//   - ReadDatabase() - Read complete database with all schemas
+//   - ReadSchema() - Read single schema with all tables
+//   - ReadTable() - Read single table with all columns and metadata
+//
+// # Usage
+//
+// Readers are instantiated with ReaderOptions containing source-specific configuration:
+//
+//	// Read from file
+//	reader := dbml.NewReader(&readers.ReaderOptions{
+//	    FilePath: "schema.dbml",
+//	})
+//	db, err := reader.ReadDatabase()
+//
+//	// Read from database
+//	reader := pgsql.NewReader(&readers.ReaderOptions{
+//	    ConnectionString: "postgres://user:pass@localhost/mydb",
+//	})
+//	db, err := reader.ReadDatabase()
+//
+// # Supported Formats
+//
+//   - dbml: Database Markup Language files
+//   - dctx: DCTX schema files
+//   - drawdb: DrawDB JSON format
+//   - graphql: GraphQL schema definition language
+//   - json: JSON database schema
+//   - yaml: YAML database schema
+//   - gorm: Go GORM model structs
+//   - bun: Go Bun model structs
+//   - drizzle: TypeScript Drizzle ORM schemas
+//   - prisma: Prisma schema language
+//   - typeorm: TypeScript TypeORM entities
+//   - pgsql: PostgreSQL live database introspection
+//   - sqlite: SQLite database files
+package readers

pkg/readers/sqlite/README.md

@@ -0,0 +1,75 @@
+# SQLite Reader
+
+Reads database schema from SQLite database files.
+
+## Usage
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
+)
+
+// Using file path
+options := &readers.ReaderOptions{
+    FilePath: "path/to/database.db",
+}
+
+reader := sqlite.NewReader(options)
+db, err := reader.ReadDatabase()
+
+// Or using connection string
+options := &readers.ReaderOptions{
+    ConnectionString: "path/to/database.db",
+}
+```
+
+## Features
+
+- Reads tables with columns and data types
+- Reads views with definitions
+- Reads primary keys
+- Reads foreign keys with CASCADE actions
+- Reads indexes (non-auto-generated)
+- Maps SQLite types to canonical types
+- Derives relationships from foreign keys
+
+## SQLite Specifics
+
+- SQLite doesn't support schemas, creates single "main" schema
+- Uses pure Go driver (modernc.org/sqlite) - no CGo required
+- Supports both file path and connection string
+- Auto-increment detection for INTEGER PRIMARY KEY columns
+- Foreign keys require `PRAGMA foreign_keys = ON` to be set
+
+## Example Schema
+
+```sql
+PRAGMA foreign_keys = ON;
+
+CREATE TABLE users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    username VARCHAR(50) NOT NULL UNIQUE,
+    email VARCHAR(100) NOT NULL
+);
+
+CREATE TABLE posts (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    title VARCHAR(200) NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+```
+
+## Type Mappings
+
+| SQLite Type | Canonical Type |
+|-------------|---------------|
+| INTEGER, INT | int |
+| BIGINT | int64 |
+| REAL, DOUBLE | float64 |
+| TEXT, VARCHAR | string |
+| BLOB | bytea |
+| BOOLEAN | bool |
+| DATE | date |
+| DATETIME, TIMESTAMP | timestamp |

pkg/readers/sqlite/queries.go

@@ -0,0 +1,306 @@
+package sqlite
+
+import (
+	"fmt"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// queryTables retrieves all tables from the SQLite database
+func (r *Reader) queryTables() ([]*models.Table, error) {
+	query := `
+		SELECT name
+		FROM sqlite_master
+		WHERE type = 'table'
+		  AND name NOT LIKE 'sqlite_%'
+		ORDER BY name
+	`
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	tables := make([]*models.Table, 0)
+	for rows.Next() {
+		var tableName string
+
+		if err := rows.Scan(&tableName); err != nil {
+			return nil, err
+		}
+
+		table := models.InitTable(tableName, "main")
+		tables = append(tables, table)
+	}
+
+	return tables, rows.Err()
+}
+
+// queryViews retrieves all views from the SQLite database
+func (r *Reader) queryViews() ([]*models.View, error) {
+	query := `
+		SELECT name, sql
+		FROM sqlite_master
+		WHERE type = 'view'
+		ORDER BY name
+	`
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	views := make([]*models.View, 0)
+	for rows.Next() {
+		var viewName string
+		var sql *string
+
+		if err := rows.Scan(&viewName, &sql); err != nil {
+			return nil, err
+		}
+
+		view := models.InitView(viewName, "main")
+		if sql != nil {
+			view.Definition = *sql
+		}
+
+		views = append(views, view)
+	}
+
+	return views, rows.Err()
+}
+
+// queryColumns retrieves all columns for a given table or view
+func (r *Reader) queryColumns(tableName string) (map[string]*models.Column, error) {
+	query := fmt.Sprintf("PRAGMA table_info(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	columns := make(map[string]*models.Column)
+
+	for rows.Next() {
+		var cid int
+		var name, dataType string
+		var notNull, pk int
+		var defaultValue *string
+
+		if err := rows.Scan(&cid, &name, &dataType, &notNull, &defaultValue, &pk); err != nil {
+			return nil, err
+		}
+
+		column := models.InitColumn(name, tableName, "main")
+		column.Type = r.mapDataType(strings.ToUpper(dataType))
+		column.NotNull = (notNull == 1)
+		column.IsPrimaryKey = (pk > 0)
+		column.Sequence = uint(cid + 1)
+
+		if defaultValue != nil {
+			column.Default = *defaultValue
+		}
+
+		// Check for autoincrement (SQLite uses INTEGER PRIMARY KEY AUTOINCREMENT)
+		if pk > 0 && strings.EqualFold(dataType, "INTEGER") {
+			column.AutoIncrement = r.isAutoIncrement(tableName, name)
+		}
+
+		columns[name] = column
+	}
+
+	return columns, rows.Err()
+}
+
+// isAutoIncrement checks if a column is autoincrement
+func (r *Reader) isAutoIncrement(tableName, columnName string) bool {
+	// Check sqlite_sequence table or parse CREATE TABLE statement
+	query := `
+		SELECT sql
+		FROM sqlite_master
+		WHERE type = 'table' AND name = ?
+	`
+
+	var sql string
+	err := r.db.QueryRowContext(r.ctx, query, tableName).Scan(&sql)
+	if err != nil {
+		return false
+	}
+
+	// Check if the SQL contains AUTOINCREMENT for this column
+	return strings.Contains(strings.ToUpper(sql), strings.ToUpper(columnName)+" INTEGER PRIMARY KEY AUTOINCREMENT") ||
+		strings.Contains(strings.ToUpper(sql), strings.ToUpper(columnName)+" INTEGER AUTOINCREMENT")
+}
+
+// queryPrimaryKey retrieves the primary key constraint for a table
+func (r *Reader) queryPrimaryKey(tableName string) (*models.Constraint, error) {
+	query := fmt.Sprintf("PRAGMA table_info(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var pkColumns []string
+
+	for rows.Next() {
+		var cid int
+		var name, dataType string
+		var notNull, pk int
+		var defaultValue *string
+
+		if err := rows.Scan(&cid, &name, &dataType, &notNull, &defaultValue, &pk); err != nil {
+			return nil, err
+		}
+
+		if pk > 0 {
+			pkColumns = append(pkColumns, name)
+		}
+	}
+
+	if len(pkColumns) == 0 {
+		return nil, nil
+	}
+
+	// Create primary key constraint
+	constraintName := fmt.Sprintf("%s_pkey", tableName)
+	constraint := models.InitConstraint(constraintName, models.PrimaryKeyConstraint)
+	constraint.Schema = "main"
+	constraint.Table = tableName
+	constraint.Columns = pkColumns
+
+	return constraint, rows.Err()
+}
+
+// queryForeignKeys retrieves all foreign key constraints for a table
+func (r *Reader) queryForeignKeys(tableName string) ([]*models.Constraint, error) {
+	query := fmt.Sprintf("PRAGMA foreign_key_list(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	// Group foreign keys by id (since composite FKs have multiple rows)
+	fkMap := make(map[int]*models.Constraint)
+
+	for rows.Next() {
+		var id, seq int
+		var referencedTable, fromColumn, toColumn string
+		var onUpdate, onDelete, match string
+
+		if err := rows.Scan(&id, &seq, &referencedTable, &fromColumn, &toColumn, &onUpdate, &onDelete, &match); err != nil {
+			return nil, err
+		}
+
+		if _, exists := fkMap[id]; !exists {
+			constraintName := fmt.Sprintf("%s_%s_fkey", tableName, referencedTable)
+			if id > 0 {
+				constraintName = fmt.Sprintf("%s_%s_fkey_%d", tableName, referencedTable, id)
+			}
+
+			constraint := models.InitConstraint(constraintName, models.ForeignKeyConstraint)
+			constraint.Schema = "main"
+			constraint.Table = tableName
+			constraint.ReferencedSchema = "main"
+			constraint.ReferencedTable = referencedTable
+			constraint.OnUpdate = onUpdate
+			constraint.OnDelete = onDelete
+			constraint.Columns = []string{}
+			constraint.ReferencedColumns = []string{}
+
+			fkMap[id] = constraint
+		}
+
+		// Add column to the constraint
+		fkMap[id].Columns = append(fkMap[id].Columns, fromColumn)
+		fkMap[id].ReferencedColumns = append(fkMap[id].ReferencedColumns, toColumn)
+	}
+
+	// Convert map to slice
+	foreignKeys := make([]*models.Constraint, 0, len(fkMap))
+	for _, fk := range fkMap {
+		foreignKeys = append(foreignKeys, fk)
+	}
+
+	return foreignKeys, rows.Err()
+}
+
+// queryIndexes retrieves all indexes for a table
+func (r *Reader) queryIndexes(tableName string) ([]*models.Index, error) {
+	query := fmt.Sprintf("PRAGMA index_list(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	indexes := make([]*models.Index, 0)
+
+	for rows.Next() {
+		var seq int
+		var name string
+		var unique int
+		var origin string
+		var partial int
+
+		if err := rows.Scan(&seq, &name, &unique, &origin, &partial); err != nil {
+			return nil, err
+		}
+
+		// Skip auto-generated indexes (origin = 'pk' for primary keys, etc.)
+		// origin: c = CREATE INDEX, u = UNIQUE constraint, pk = PRIMARY KEY
+		if origin == "pk" || origin == "u" {
+			continue
+		}
+
+		index := models.InitIndex(name, tableName, "main")
+		index.Unique = (unique == 1)
+
+		// Get index columns
+		columns, err := r.queryIndexColumns(name)
+		if err != nil {
+			return nil, err
+		}
+		index.Columns = columns
+
+		indexes = append(indexes, index)
+	}
+
+	return indexes, rows.Err()
+}
+
+// queryIndexColumns retrieves the columns for a specific index
+func (r *Reader) queryIndexColumns(indexName string) ([]string, error) {
+	query := fmt.Sprintf("PRAGMA index_info(%s)", indexName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	columns := make([]string, 0)
+
+	for rows.Next() {
+		var seqno, cid int
+		var name *string
+
+		if err := rows.Scan(&seqno, &cid, &name); err != nil {
+			return nil, err
+		}
+
+		if name != nil {
+			columns = append(columns, *name)
+		}
+	}
+
+	return columns, rows.Err()
+}

pkg/readers/sqlite/reader.go

@@ -0,0 +1,261 @@
+package sqlite
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"path/filepath"
+
+	_ "modernc.org/sqlite" // SQLite driver
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+// Reader implements the readers.Reader interface for SQLite databases
+type Reader struct {
+	options *readers.ReaderOptions
+	db      *sql.DB
+	ctx     context.Context
+}
+
+// NewReader creates a new SQLite reader
+func NewReader(options *readers.ReaderOptions) *Reader {
+	return &Reader{
+		options: options,
+		ctx:     context.Background(),
+	}
+}
+
+// ReadDatabase reads the entire database schema from SQLite
+func (r *Reader) ReadDatabase() (*models.Database, error) {
+	// Validate file path or connection string
+	dbPath := r.options.FilePath
+	if dbPath == "" && r.options.ConnectionString != "" {
+		dbPath = r.options.ConnectionString
+	}
+	if dbPath == "" {
+		return nil, fmt.Errorf("file path or connection string is required")
+	}
+
+	// Connect to the database
+	if err := r.connect(dbPath); err != nil {
+		return nil, fmt.Errorf("failed to connect: %w", err)
+	}
+	defer r.close()
+
+	// Get database name from file path
+	dbName := filepath.Base(dbPath)
+	if dbName == "" {
+		dbName = "sqlite"
+	}
+
+	// Initialize database model
+	db := models.InitDatabase(dbName)
+	db.DatabaseType = models.SqlLiteDatabaseType
+	db.SourceFormat = "sqlite"
+
+	// Get SQLite version
+	var version string
+	err := r.db.QueryRowContext(r.ctx, "SELECT sqlite_version()").Scan(&version)
+	if err == nil {
+		db.DatabaseVersion = version
+	}
+
+	// SQLite doesn't have schemas, so we create a single "main" schema
+	schema := models.InitSchema("main")
+	schema.RefDatabase = db
+
+	// Query tables
+	tables, err := r.queryTables()
+	if err != nil {
+		return nil, fmt.Errorf("failed to query tables: %w", err)
+	}
+	schema.Tables = tables
+
+	// Query views
+	views, err := r.queryViews()
+	if err != nil {
+		return nil, fmt.Errorf("failed to query views: %w", err)
+	}
+	schema.Views = views
+
+	// Query columns for tables and views
+	for _, table := range schema.Tables {
+		columns, err := r.queryColumns(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query columns for table %s: %w", table.Name, err)
+		}
+		table.Columns = columns
+		table.RefSchema = schema
+
+		// Query primary key
+		pk, err := r.queryPrimaryKey(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query primary key for table %s: %w", table.Name, err)
+		}
+		if pk != nil {
+			table.Constraints[pk.Name] = pk
+			// Mark columns as primary key and not null
+			for _, colName := range pk.Columns {
+				if col, exists := table.Columns[colName]; exists {
+					col.IsPrimaryKey = true
+					col.NotNull = true
+				}
+			}
+		}
+
+		// Query foreign keys
+		foreignKeys, err := r.queryForeignKeys(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query foreign keys for table %s: %w", table.Name, err)
+		}
+		for _, fk := range foreignKeys {
+			table.Constraints[fk.Name] = fk
+			// Derive relationship from foreign key
+			r.deriveRelationship(table, fk)
+		}
+
+		// Query indexes
+		indexes, err := r.queryIndexes(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query indexes for table %s: %w", table.Name, err)
+		}
+		for _, idx := range indexes {
+			table.Indexes[idx.Name] = idx
+		}
+	}
+
+	// Query columns for views
+	for _, view := range schema.Views {
+		columns, err := r.queryColumns(view.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query columns for view %s: %w", view.Name, err)
+		}
+		view.Columns = columns
+		view.RefSchema = schema
+	}
+
+	// Add schema to database
+	db.Schemas = append(db.Schemas, schema)
+
+	return db, nil
+}
+
+// ReadSchema reads a single schema (returns the main schema from the database)
+func (r *Reader) ReadSchema() (*models.Schema, error) {
+	db, err := r.ReadDatabase()
+	if err != nil {
+		return nil, err
+	}
+	if len(db.Schemas) == 0 {
+		return nil, fmt.Errorf("no schemas found in database")
+	}
+	return db.Schemas[0], nil
+}
+
+// ReadTable reads a single table (returns the first table from the schema)
+func (r *Reader) ReadTable() (*models.Table, error) {
+	schema, err := r.ReadSchema()
+	if err != nil {
+		return nil, err
+	}
+	if len(schema.Tables) == 0 {
+		return nil, fmt.Errorf("no tables found in schema")
+	}
+	return schema.Tables[0], nil
+}
+
+// connect establishes a connection to the SQLite database
+func (r *Reader) connect(dbPath string) error {
+	db, err := sql.Open("sqlite", dbPath)
+	if err != nil {
+		return err
+	}
+	r.db = db
+	return nil
+}
+
+// close closes the database connection
+func (r *Reader) close() {
+	if r.db != nil {
+		r.db.Close()
+	}
+}
+
+// mapDataType maps SQLite data types to canonical types
+func (r *Reader) mapDataType(sqliteType string) string {
+	// SQLite has a flexible type system, but we map common types
+	typeMap := map[string]string{
+		"INTEGER":           "int",
+		"INT":               "int",
+		"TINYINT":           "int8",
+		"SMALLINT":          "int16",
+		"MEDIUMINT":         "int",
+		"BIGINT":            "int64",
+		"UNSIGNED BIG INT":  "uint64",
+		"INT2":              "int16",
+		"INT8":              "int64",
+		"REAL":              "float64",
+		"DOUBLE":            "float64",
+		"DOUBLE PRECISION":  "float64",
+		"FLOAT":             "float32",
+		"NUMERIC":           "decimal",
+		"DECIMAL":           "decimal",
+		"BOOLEAN":           "bool",
+		"BOOL":              "bool",
+		"DATE":              "date",
+		"DATETIME":          "timestamp",
+		"TIMESTAMP":         "timestamp",
+		"TEXT":              "string",
+		"VARCHAR":           "string",
+		"CHAR":              "string",
+		"CHARACTER":         "string",
+		"VARYING CHARACTER": "string",
+		"NCHAR":             "string",
+		"NVARCHAR":          "string",
+		"CLOB":              "text",
+		"BLOB":              "bytea",
+	}
+
+	// Try exact match first
+	if mapped, exists := typeMap[sqliteType]; exists {
+		return mapped
+	}
+
+	// Try case-insensitive match for common types
+	sqliteTypeUpper := sqliteType
+	if len(sqliteType) > 0 {
+		// Extract base type (e.g., "VARCHAR(255)" -> "VARCHAR")
+		for baseType := range typeMap {
+			if len(sqliteTypeUpper) >= len(baseType) && sqliteTypeUpper[:len(baseType)] == baseType {
+				return typeMap[baseType]
+			}
+		}
+	}
+
+	// Default to string for unknown types
+	return "string"
+}
+
+// deriveRelationship creates a relationship from a foreign key constraint
+func (r *Reader) deriveRelationship(table *models.Table, fk *models.Constraint) {
+	relationshipName := fmt.Sprintf("%s_to_%s", table.Name, fk.ReferencedTable)
+
+	relationship := models.InitRelationship(relationshipName, models.OneToMany)
+	relationship.FromTable = table.Name
+	relationship.FromSchema = table.Schema
+	relationship.ToTable = fk.ReferencedTable
+	relationship.ToSchema = fk.ReferencedSchema
+	relationship.ForeignKey = fk.Name
+
+	// Store constraint actions in properties
+	if fk.OnDelete != "" {
+		relationship.Properties["on_delete"] = fk.OnDelete
+	}
+	if fk.OnUpdate != "" {
+		relationship.Properties["on_update"] = fk.OnUpdate
+	}
+
+	table.Relationships[relationshipName] = relationship
+}

pkg/readers/sqlite/reader_test.go

@@ -0,0 +1,334 @@
+package sqlite
+
+import (
+	"database/sql"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+// setupTestDatabase creates a temporary SQLite database with test data
+func setupTestDatabase(t *testing.T) string {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "test.db")
+
+	db, err := sql.Open("sqlite", dbPath)
+	require.NoError(t, err)
+	defer db.Close()
+
+	// Create test schema
+	schema := `
+		PRAGMA foreign_keys = ON;
+
+		CREATE TABLE users (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			username VARCHAR(50) NOT NULL UNIQUE,
+			email VARCHAR(100) NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		);
+
+		CREATE TABLE posts (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			user_id INTEGER NOT NULL,
+			title VARCHAR(200) NOT NULL,
+			content TEXT,
+			published BOOLEAN DEFAULT 0,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+		);
+
+		CREATE TABLE comments (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			post_id INTEGER NOT NULL,
+			user_id INTEGER NOT NULL,
+			comment TEXT NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (post_id) REFERENCES posts(id) ON DELETE CASCADE,
+			FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+		);
+
+		CREATE INDEX idx_posts_user_id ON posts(user_id);
+		CREATE INDEX idx_comments_post_id ON comments(post_id);
+		CREATE UNIQUE INDEX idx_users_email ON users(email);
+
+		CREATE VIEW user_post_count AS
+		SELECT u.id, u.username, COUNT(p.id) as post_count
+		FROM users u
+		LEFT JOIN posts p ON u.id = p.user_id
+		GROUP BY u.id, u.username;
+	`
+
+	_, err = db.Exec(schema)
+	require.NoError(t, err)
+
+	return dbPath
+}
+
+func TestReader_ReadDatabase(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Check database metadata
+	assert.Equal(t, "test.db", db.Name)
+	assert.Equal(t, models.SqlLiteDatabaseType, db.DatabaseType)
+	assert.Equal(t, "sqlite", db.SourceFormat)
+	assert.NotEmpty(t, db.DatabaseVersion)
+
+	// Check schemas (SQLite should have a single "main" schema)
+	require.Len(t, db.Schemas, 1)
+	schema := db.Schemas[0]
+	assert.Equal(t, "main", schema.Name)
+
+	// Check tables
+	assert.Len(t, schema.Tables, 3)
+	tableNames := make([]string, len(schema.Tables))
+	for i, table := range schema.Tables {
+		tableNames[i] = table.Name
+	}
+	assert.Contains(t, tableNames, "users")
+	assert.Contains(t, tableNames, "posts")
+	assert.Contains(t, tableNames, "comments")
+
+	// Check views
+	assert.Len(t, schema.Views, 1)
+	assert.Equal(t, "user_post_count", schema.Views[0].Name)
+	assert.NotEmpty(t, schema.Views[0].Definition)
+}
+
+func TestReader_ReadTable_Users(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find users table
+	var usersTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "users" {
+			usersTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, usersTable)
+	assert.Equal(t, "users", usersTable.Name)
+	assert.Equal(t, "main", usersTable.Schema)
+
+	// Check columns
+	assert.Len(t, usersTable.Columns, 4)
+
+	// Check id column
+	idCol, exists := usersTable.Columns["id"]
+	require.True(t, exists)
+	assert.Equal(t, "int", idCol.Type)
+	assert.True(t, idCol.IsPrimaryKey)
+	assert.True(t, idCol.AutoIncrement)
+	assert.True(t, idCol.NotNull)
+
+	// Check username column
+	usernameCol, exists := usersTable.Columns["username"]
+	require.True(t, exists)
+	assert.Equal(t, "string", usernameCol.Type)
+	assert.True(t, usernameCol.NotNull)
+	assert.False(t, usernameCol.IsPrimaryKey)
+
+	// Check email column
+	emailCol, exists := usersTable.Columns["email"]
+	require.True(t, exists)
+	assert.Equal(t, "string", emailCol.Type)
+	assert.True(t, emailCol.NotNull)
+
+	// Check primary key constraint
+	assert.Len(t, usersTable.Constraints, 1)
+	pkConstraint, exists := usersTable.Constraints["users_pkey"]
+	require.True(t, exists)
+	assert.Equal(t, models.PrimaryKeyConstraint, pkConstraint.Type)
+	assert.Equal(t, []string{"id"}, pkConstraint.Columns)
+
+	// Check indexes (should have unique index on email and username)
+	assert.GreaterOrEqual(t, len(usersTable.Indexes), 1)
+}
+
+func TestReader_ReadTable_Posts(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find posts table
+	var postsTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "posts" {
+			postsTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, postsTable)
+
+	// Check columns
+	assert.Len(t, postsTable.Columns, 6)
+
+	// Check foreign key constraint
+	hasForeignKey := false
+	for _, constraint := range postsTable.Constraints {
+		if constraint.Type == models.ForeignKeyConstraint {
+			hasForeignKey = true
+			assert.Equal(t, "users", constraint.ReferencedTable)
+			assert.Equal(t, "CASCADE", constraint.OnDelete)
+		}
+	}
+	assert.True(t, hasForeignKey, "Posts table should have a foreign key constraint")
+
+	// Check relationships
+	assert.GreaterOrEqual(t, len(postsTable.Relationships), 1)
+
+	// Check indexes
+	hasUserIdIndex := false
+	for _, index := range postsTable.Indexes {
+		if index.Name == "idx_posts_user_id" {
+			hasUserIdIndex = true
+			assert.Contains(t, index.Columns, "user_id")
+		}
+	}
+	assert.True(t, hasUserIdIndex, "Posts table should have idx_posts_user_id index")
+}
+
+func TestReader_ReadTable_Comments(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find comments table
+	var commentsTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "comments" {
+			commentsTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, commentsTable)
+
+	// Check foreign key constraints (should have 2)
+	fkCount := 0
+	for _, constraint := range commentsTable.Constraints {
+		if constraint.Type == models.ForeignKeyConstraint {
+			fkCount++
+		}
+	}
+	assert.Equal(t, 2, fkCount, "Comments table should have 2 foreign key constraints")
+}
+
+func TestReader_ReadSchema(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	schema, err := reader.ReadSchema()
+
+	require.NoError(t, err)
+	require.NotNil(t, schema)
+	assert.Equal(t, "main", schema.Name)
+	assert.Len(t, schema.Tables, 3)
+	assert.Len(t, schema.Views, 1)
+}
+
+func TestReader_ReadTable(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	table, err := reader.ReadTable()
+
+	require.NoError(t, err)
+	require.NotNil(t, table)
+	assert.NotEmpty(t, table.Name)
+	assert.NotEmpty(t, table.Columns)
+}
+
+func TestReader_ConnectionString(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		ConnectionString: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+	assert.Len(t, db.Schemas, 1)
+}
+
+func TestReader_InvalidPath(t *testing.T) {
+	options := &readers.ReaderOptions{
+		FilePath: "/nonexistent/path/to/database.db",
+	}
+
+	reader := NewReader(options)
+	_, err := reader.ReadDatabase()
+
+	assert.Error(t, err)
+}
+
+func TestReader_MissingPath(t *testing.T) {
+	options := &readers.ReaderOptions{}
+
+	reader := NewReader(options)
+	_, err := reader.ReadDatabase()
+
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "file path or connection string is required")
+}

pkg/reflectutil/doc.go

@@ -0,0 +1,36 @@
+// Package reflectutil provides reflection utilities for analyzing Go code structures.
+//
+// # Overview
+//
+// The reflectutil package offers helper functions for working with Go's reflection
+// capabilities, particularly for parsing Go struct definitions and extracting type
+// information. This is used by readers that parse ORM model files.
+//
+// # Features
+//
+//   - Struct tag parsing and extraction
+//   - Type information analysis
+//   - Field metadata extraction
+//   - ORM tag interpretation (GORM, Bun, etc.)
+//
+// # Usage
+//
+// This package is primarily used internally by readers like GORM and Bun to parse
+// Go struct definitions and convert them to database schema models.
+//
+//	// Example: Parse struct tags
+//	tags := reflectutil.ParseStructTags(field)
+//	columnName := tags.Get("db")
+//
+// # Supported ORM Tags
+//
+// The package understands tag conventions from:
+//   - GORM (gorm tag)
+//   - Bun (bun tag)
+//   - Standard database/sql (db tag)
+//
+// # Purpose
+//
+// This package enables RelSpec to read existing ORM models and convert them to
+// a unified schema representation for transformation to other formats.
+package reflectutil

pkg/reflectutil/helpers_test.go

@@ -0,0 +1,490 @@
+package reflectutil
+
+import (
+	"reflect"
+	"testing"
+)
+
+type testStruct struct {
+	Name    string
+	Age     int
+	Active  bool
+	Nested  *nestedStruct
+	Private string
+}
+
+type nestedStruct struct {
+	Value string
+	Count int
+}
+
+func TestDeref(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     interface{}
+		wantValid bool
+		wantKind  reflect.Kind
+	}{
+		{
+			name:      "non-pointer int",
+			input:     42,
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "single pointer",
+			input:     ptrInt(42),
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "double pointer",
+			input:     ptrPtr(ptrInt(42)),
+			wantValid: true,
+			wantKind:  reflect.Int,
+		},
+		{
+			name:      "nil pointer",
+			input:     (*int)(nil),
+			wantValid: false,
+			wantKind:  reflect.Ptr,
+		},
+		{
+			name:      "string",
+			input:     "test",
+			wantValid: true,
+			wantKind:  reflect.String,
+		},
+		{
+			name:      "struct",
+			input:     testStruct{Name: "test"},
+			wantValid: true,
+			wantKind:  reflect.Struct,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			v := reflect.ValueOf(tt.input)
+			got, valid := Deref(v)
+
+			if valid != tt.wantValid {
+				t.Errorf("Deref() valid = %v, want %v", valid, tt.wantValid)
+			}
+
+			if got.Kind() != tt.wantKind {
+				t.Errorf("Deref() kind = %v, want %v", got.Kind(), tt.wantKind)
+			}
+		})
+	}
+}
+
+func TestDerefInterface(t *testing.T) {
+	i := 42
+	pi := &i
+	ppi := &pi
+
+	tests := []struct {
+		name     string
+		input    interface{}
+		wantKind reflect.Kind
+	}{
+		{"int", 42, reflect.Int},
+		{"pointer to int", &i, reflect.Int},
+		{"double pointer to int", ppi, reflect.Int},
+		{"string", "test", reflect.String},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DerefInterface(tt.input)
+			if got.Kind() != tt.wantKind {
+				t.Errorf("DerefInterface() kind = %v, want %v", got.Kind(), tt.wantKind)
+			}
+		})
+	}
+}
+
+func TestGetFieldValue(t *testing.T) {
+	ts := testStruct{
+		Name:   "John",
+		Age:    30,
+		Active: true,
+		Nested: &nestedStruct{Value: "nested", Count: 5},
+	}
+
+	tests := []struct {
+		name  string
+		item  interface{}
+		field string
+		want  interface{}
+	}{
+		{"struct field Name", ts, "Name", "John"},
+		{"struct field Age", ts, "Age", 30},
+		{"struct field Active", ts, "Active", true},
+		{"struct non-existent field", ts, "NonExistent", nil},
+		{"pointer to struct", &ts, "Name", "John"},
+		{"map string key", map[string]string{"key": "value"}, "key", "value"},
+		{"map int key", map[string]int{"count": 42}, "count", 42},
+		{"map non-existent key", map[string]string{"key": "value"}, "missing", nil},
+		{"nil pointer", (*testStruct)(nil), "Name", nil},
+		{"non-struct non-map", 42, "field", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetFieldValue(tt.item, tt.field)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetFieldValue() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsSliceOrArray(t *testing.T) {
+	arr := [3]int{1, 2, 3}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		want  bool
+	}{
+		{"slice", []int{1, 2, 3}, true},
+		{"array", arr, true},
+		{"pointer to slice", &[]int{1, 2, 3}, true},
+		{"string", "test", false},
+		{"int", 42, false},
+		{"map", map[string]int{}, false},
+		{"nil slice", ([]int)(nil), true}, // nil slice is still Kind==Slice
+		{"nil pointer", (*[]int)(nil), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsSliceOrArray(tt.input)
+			if got != tt.want {
+				t.Errorf("IsSliceOrArray() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsMap(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  bool
+	}{
+		{"map[string]int", map[string]int{"a": 1}, true},
+		{"map[int]string", map[int]string{1: "a"}, true},
+		{"pointer to map", &map[string]int{"a": 1}, true},
+		{"slice", []int{1, 2, 3}, false},
+		{"string", "test", false},
+		{"int", 42, false},
+		{"nil map", (map[string]int)(nil), true}, // nil map is still Kind==Map
+		{"nil pointer", (*map[string]int)(nil), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := IsMap(tt.input)
+			if got != tt.want {
+				t.Errorf("IsMap() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceLen(t *testing.T) {
+	arr := [3]int{1, 2, 3}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int
+	}{
+		{"slice length 3", []int{1, 2, 3}, 3},
+		{"empty slice", []int{}, 0},
+		{"array length 3", arr, 3},
+		{"pointer to slice", &[]int{1, 2, 3}, 3},
+		{"not a slice", "test", 0},
+		{"int", 42, 0},
+		{"nil slice", ([]int)(nil), 0},
+		{"nil pointer", (*[]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceLen(tt.input)
+			if got != tt.want {
+				t.Errorf("SliceLen() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMapLen(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int
+	}{
+		{"map length 2", map[string]int{"a": 1, "b": 2}, 2},
+		{"empty map", map[string]int{}, 0},
+		{"pointer to map", &map[string]int{"a": 1}, 1},
+		{"not a map", []int{1, 2, 3}, 0},
+		{"string", "test", 0},
+		{"nil map", (map[string]int)(nil), 0},
+		{"nil pointer", (*map[string]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapLen(tt.input)
+			if got != tt.want {
+				t.Errorf("MapLen() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceToInterfaces(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  []interface{}
+	}{
+		{"int slice", []int{1, 2, 3}, []interface{}{1, 2, 3}},
+		{"string slice", []string{"a", "b"}, []interface{}{"a", "b"}},
+		{"empty slice", []int{}, []interface{}{}},
+		{"pointer to slice", &[]int{1, 2}, []interface{}{1, 2}},
+		{"not a slice", "test", []interface{}{}},
+		{"nil slice", ([]int)(nil), []interface{}{}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceToInterfaces(tt.input)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("SliceToInterfaces() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMapKeys(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  []interface{}
+	}{
+		{"map with keys", map[string]int{"a": 1, "b": 2}, []interface{}{"a", "b"}},
+		{"empty map", map[string]int{}, []interface{}{}},
+		{"not a map", []int{1, 2, 3}, []interface{}{}},
+		{"nil map", (map[string]int)(nil), []interface{}{}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapKeys(tt.input)
+			if len(got) != len(tt.want) {
+				t.Errorf("MapKeys() length = %v, want %v", len(got), len(tt.want))
+			}
+			// For maps, order is not guaranteed, so just check length
+		})
+	}
+}
+
+func TestMapValues(t *testing.T) {
+	tests := []struct {
+		name  string
+		input interface{}
+		want  int // length of values
+	}{
+		{"map with values", map[string]int{"a": 1, "b": 2}, 2},
+		{"empty map", map[string]int{}, 0},
+		{"not a map", []int{1, 2, 3}, 0},
+		{"nil map", (map[string]int)(nil), 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapValues(tt.input)
+			if len(got) != tt.want {
+				t.Errorf("MapValues() length = %v, want %v", len(got), tt.want)
+			}
+		})
+	}
+}
+
+func TestMapGet(t *testing.T) {
+	m := map[string]int{"a": 1, "b": 2}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		key   interface{}
+		want  interface{}
+	}{
+		{"existing key", m, "a", 1},
+		{"existing key b", m, "b", 2},
+		{"non-existing key", m, "c", nil},
+		{"pointer to map", &m, "a", 1},
+		{"not a map", []int{1, 2}, 0, nil},
+		{"nil map", (map[string]int)(nil), "a", nil},
+		{"nil pointer", (*map[string]int)(nil), "a", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := MapGet(tt.input, tt.key)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("MapGet() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSliceIndex(t *testing.T) {
+	s := []int{10, 20, 30}
+
+	tests := []struct {
+		name  string
+		slice interface{}
+		index int
+		want  interface{}
+	}{
+		{"index 0", s, 0, 10},
+		{"index 1", s, 1, 20},
+		{"index 2", s, 2, 30},
+		{"negative index", s, -1, nil},
+		{"out of bounds", s, 5, nil},
+		{"pointer to slice", &s, 1, 20},
+		{"not a slice", "test", 0, nil},
+		{"nil slice", ([]int)(nil), 0, nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := SliceIndex(tt.slice, tt.index)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("SliceIndex() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestCompareValues(t *testing.T) {
+	tests := []struct {
+		name string
+		a    interface{}
+		b    interface{}
+		want int
+	}{
+		{"both nil", nil, nil, 0},
+		{"a nil", nil, 5, -1},
+		{"b nil", 5, nil, 1},
+		{"equal strings", "abc", "abc", 0},
+		{"a less than b strings", "abc", "xyz", -1},
+		{"a greater than b strings", "xyz", "abc", 1},
+		{"equal ints", 5, 5, 0},
+		{"a less than b ints", 3, 7, -1},
+		{"a greater than b ints", 10, 5, 1},
+		{"equal floats", 3.14, 3.14, 0},
+		{"a less than b floats", 2.5, 5.5, -1},
+		{"a greater than b floats", 10.5, 5.5, 1},
+		{"equal uints", uint(5), uint(5), 0},
+		{"different types", "abc", 123, 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := CompareValues(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("CompareValues(%v, %v) = %v, want %v", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetNestedValue(t *testing.T) {
+	nested := map[string]interface{}{
+		"level1": map[string]interface{}{
+			"level2": map[string]interface{}{
+				"value": "deep",
+			},
+		},
+	}
+
+	ts := testStruct{
+		Name: "John",
+		Nested: &nestedStruct{
+			Value: "nested value",
+			Count: 42,
+		},
+	}
+
+	tests := []struct {
+		name  string
+		input interface{}
+		path  string
+		want  interface{}
+	}{
+		{"empty path", nested, "", nested},
+		{"single level map", nested, "level1", nested["level1"]},
+		{"nested map", nested, "level1.level2", map[string]interface{}{"value": "deep"}},
+		{"deep nested map", nested, "level1.level2.value", "deep"},
+		{"struct field", ts, "Name", "John"},
+		{"nested struct field", ts, "Nested", ts.Nested},
+		{"non-existent path", nested, "missing.path", nil},
+		{"nil input", nil, "path", nil},
+		{"partial missing path", nested, "level1.missing", nil},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetNestedValue(tt.input, tt.path)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetNestedValue() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDeepEqual(t *testing.T) {
+	tests := []struct {
+		name string
+		a    interface{}
+		b    interface{}
+		want bool
+	}{
+		{"equal ints", 42, 42, true},
+		{"different ints", 42, 43, false},
+		{"equal strings", "test", "test", true},
+		{"different strings", "test", "other", false},
+		{"equal slices", []int{1, 2, 3}, []int{1, 2, 3}, true},
+		{"different slices", []int{1, 2, 3}, []int{1, 2, 4}, false},
+		{"equal maps", map[string]int{"a": 1}, map[string]int{"a": 1}, true},
+		{"different maps", map[string]int{"a": 1}, map[string]int{"a": 2}, false},
+		{"both nil", nil, nil, true},
+		{"one nil", nil, 42, false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := DeepEqual(tt.a, tt.b)
+			if got != tt.want {
+				t.Errorf("DeepEqual(%v, %v) = %v, want %v", tt.a, tt.b, got, tt.want)
+			}
+		})
+	}
+}
+
+// Helper functions
+func ptrInt(i int) *int {
+	return &i
+}
+
+func ptrPtr(p *int) **int {
+	return &p
+}

pkg/transform/doc.go

@@ -0,0 +1,34 @@
+// Package transform provides validation and transformation utilities for database models.
+//
+// # Overview
+//
+// The transform package contains a Transformer type that provides methods for validating
+// and normalizing database schemas. It ensures schema correctness and consistency across
+// different format conversions.
+//
+// # Features
+//
+//   - Database validation (structure and naming conventions)
+//   - Schema validation (completeness and integrity)
+//   - Table validation (column definitions and constraints)
+//   - Data type normalization
+//
+// # Usage
+//
+//	transformer := transform.NewTransformer()
+//	err := transformer.ValidateDatabase(db)
+//	if err != nil {
+//	    log.Fatal("Invalid database schema:", err)
+//	}
+//
+// # Validation Scope
+//
+// The transformer validates:
+//   - Required fields presence
+//   - Naming convention adherence
+//   - Data type compatibility
+//   - Constraint consistency
+//   - Relationship integrity
+//
+// Note: Some validation methods are currently stubs and will be implemented as needed.
+package transform

pkg/ui/doc.go

@@ -0,0 +1,57 @@
+// Package ui provides an interactive terminal user interface (TUI) for editing database schemas.
+//
+// # Overview
+//
+// The ui package implements a full-featured terminal-based schema editor using tview,
+// allowing users to visually create, modify, and manage database schemas without writing
+// code or SQL.
+//
+// # Features
+//
+// The schema editor supports:
+//   - Database management: Edit name, description, and properties
+//   - Schema management: Create, edit, delete schemas
+//   - Table management: Create, edit, delete tables
+//   - Column management: Add, modify, delete columns with full property support
+//   - Relationship management: Define and edit table relationships
+//   - Domain management: Organize tables into logical domains
+//   - Import & merge: Combine schemas from multiple sources
+//   - Save: Export to any supported format
+//
+// # Architecture
+//
+// The package is organized into several components:
+//   - editor.go: Main editor and application lifecycle
+//   - *_screens.go: UI screens for each entity type
+//   - *_dataops.go: Business logic and data operations
+//   - dialogs.go: Reusable dialog components
+//   - load_save_screens.go: File I/O and format selection
+//   - main_menu.go: Primary navigation menu
+//
+// # Usage
+//
+//	editor := ui.NewSchemaEditor(database)
+//	if err := editor.Run(); err != nil {
+//	    log.Fatal(err)
+//	}
+//
+// Or with pre-configured load/save options:
+//
+//	editor := ui.NewSchemaEditorWithConfigs(database, loadConfig, saveConfig)
+//	if err := editor.Run(); err != nil {
+//	    log.Fatal(err)
+//	}
+//
+// # Navigation
+//
+//   - Arrow keys: Navigate between items
+//   - Enter: Select/edit item
+//   - Tab/Shift+Tab: Navigate between buttons
+//   - Escape: Go back/cancel
+//   - Letter shortcuts: Quick actions (e.g., 'n' for new, 'e' for edit, 'd' for delete)
+//
+// # Integration
+//
+// The editor integrates with all readers and writers, supporting load/save operations
+// for any format supported by RelSpec (DBML, PostgreSQL, GORM, Prisma, etc.).
+package ui

pkg/ui/relation_dataops.go

@@ -0,0 +1,115 @@
+package ui
+
+import "git.warky.dev/wdevs/relspecgo/pkg/models"
+
+// Relationship data operations - business logic for relationship management
+
+// CreateRelationship creates a new relationship and adds it to a table
+func (se *SchemaEditor) CreateRelationship(schemaIndex, tableIndex int, rel *models.Relationship) *models.Relationship {
+	if schemaIndex < 0 || schemaIndex >= len(se.db.Schemas) {
+		return nil
+	}
+
+	schema := se.db.Schemas[schemaIndex]
+	if tableIndex < 0 || tableIndex >= len(schema.Tables) {
+		return nil
+	}
+
+	table := schema.Tables[tableIndex]
+	if table.Relationships == nil {
+		table.Relationships = make(map[string]*models.Relationship)
+	}
+
+	table.Relationships[rel.Name] = rel
+	table.UpdateDate()
+	return rel
+}
+
+// UpdateRelationship updates an existing relationship
+func (se *SchemaEditor) UpdateRelationship(schemaIndex, tableIndex int, oldName string, rel *models.Relationship) bool {
+	if schemaIndex < 0 || schemaIndex >= len(se.db.Schemas) {
+		return false
+	}
+
+	schema := se.db.Schemas[schemaIndex]
+	if tableIndex < 0 || tableIndex >= len(schema.Tables) {
+		return false
+	}
+
+	table := schema.Tables[tableIndex]
+	if table.Relationships == nil {
+		return false
+	}
+
+	// Delete old entry if name changed
+	if oldName != rel.Name {
+		delete(table.Relationships, oldName)
+	}
+
+	table.Relationships[rel.Name] = rel
+	table.UpdateDate()
+	return true
+}
+
+// DeleteRelationship removes a relationship from a table
+func (se *SchemaEditor) DeleteRelationship(schemaIndex, tableIndex int, relName string) bool {
+	if schemaIndex < 0 || schemaIndex >= len(se.db.Schemas) {
+		return false
+	}
+
+	schema := se.db.Schemas[schemaIndex]
+	if tableIndex < 0 || tableIndex >= len(schema.Tables) {
+		return false
+	}
+
+	table := schema.Tables[tableIndex]
+	if table.Relationships == nil {
+		return false
+	}
+
+	delete(table.Relationships, relName)
+	table.UpdateDate()
+	return true
+}
+
+// GetRelationship returns a relationship by name
+func (se *SchemaEditor) GetRelationship(schemaIndex, tableIndex int, relName string) *models.Relationship {
+	if schemaIndex < 0 || schemaIndex >= len(se.db.Schemas) {
+		return nil
+	}
+
+	schema := se.db.Schemas[schemaIndex]
+	if tableIndex < 0 || tableIndex >= len(schema.Tables) {
+		return nil
+	}
+
+	table := schema.Tables[tableIndex]
+	if table.Relationships == nil {
+		return nil
+	}
+
+	return table.Relationships[relName]
+}
+
+// GetRelationshipNames returns all relationship names for a table
+func (se *SchemaEditor) GetRelationshipNames(schemaIndex, tableIndex int) []string {
+	if schemaIndex < 0 || schemaIndex >= len(se.db.Schemas) {
+		return nil
+	}
+
+	schema := se.db.Schemas[schemaIndex]
+	if tableIndex < 0 || tableIndex >= len(schema.Tables) {
+		return nil
+	}
+
+	table := schema.Tables[tableIndex]
+	if table.Relationships == nil {
+		return nil
+	}
+
+	names := make([]string, 0, len(table.Relationships))
+	for name := range table.Relationships {
+		names = append(names, name)
+	}
+	return names
+}

pkg/ui/relation_screens.go

@@ -0,0 +1,486 @@
+package ui
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/gdamore/tcell/v2"
+	"github.com/rivo/tview"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// showRelationshipList displays all relationships for a table
+func (se *SchemaEditor) showRelationshipList(schemaIndex, tableIndex int) {
+	table := se.GetTable(schemaIndex, tableIndex)
+	if table == nil {
+		return
+	}
+
+	flex := tview.NewFlex().SetDirection(tview.FlexRow)
+
+	// Title
+	title := tview.NewTextView().
+		SetText(fmt.Sprintf("[::b]Relationships for Table: %s", table.Name)).
+		SetDynamicColors(true).
+		SetTextAlign(tview.AlignCenter)
+
+	// Create relationships table
+	relTable := tview.NewTable().SetBorders(true).SetSelectable(true, false).SetFixed(1, 0)
+
+	// Add header row
+	headers := []string{"Name", "Type", "From Columns", "To Table", "To Columns", "Description"}
+	headerWidths := []int{20, 15, 20, 20, 20}
+	for i, header := range headers {
+		padding := ""
+		if i < len(headerWidths) {
+			padding = strings.Repeat(" ", headerWidths[i]-len(header))
+		}
+		cell := tview.NewTableCell(header + padding).
+			SetTextColor(tcell.ColorYellow).
+			SetSelectable(false).
+			SetAlign(tview.AlignLeft)
+		relTable.SetCell(0, i, cell)
+	}
+
+	// Get relationship names
+	relNames := se.GetRelationshipNames(schemaIndex, tableIndex)
+	for row, relName := range relNames {
+		rel := table.Relationships[relName]
+
+		// Name
+		nameStr := fmt.Sprintf("%-20s", rel.Name)
+		nameCell := tview.NewTableCell(nameStr).SetSelectable(true)
+		relTable.SetCell(row+1, 0, nameCell)
+
+		// Type
+		typeStr := fmt.Sprintf("%-15s", string(rel.Type))
+		typeCell := tview.NewTableCell(typeStr).SetSelectable(true)
+		relTable.SetCell(row+1, 1, typeCell)
+
+		// From Columns
+		fromColsStr := strings.Join(rel.FromColumns, ", ")
+		fromColsStr = fmt.Sprintf("%-20s", fromColsStr)
+		fromColsCell := tview.NewTableCell(fromColsStr).SetSelectable(true)
+		relTable.SetCell(row+1, 2, fromColsCell)
+
+		// To Table
+		toTableStr := rel.ToTable
+		if rel.ToSchema != "" && rel.ToSchema != table.Schema {
+			toTableStr = rel.ToSchema + "." + rel.ToTable
+		}
+		toTableStr = fmt.Sprintf("%-20s", toTableStr)
+		toTableCell := tview.NewTableCell(toTableStr).SetSelectable(true)
+		relTable.SetCell(row+1, 3, toTableCell)
+
+		// To Columns
+		toColsStr := strings.Join(rel.ToColumns, ", ")
+		toColsStr = fmt.Sprintf("%-20s", toColsStr)
+		toColsCell := tview.NewTableCell(toColsStr).SetSelectable(true)
+		relTable.SetCell(row+1, 4, toColsCell)
+
+		// Description
+		descCell := tview.NewTableCell(rel.Description).SetSelectable(true)
+		relTable.SetCell(row+1, 5, descCell)
+	}
+
+	relTable.SetTitle(" Relationships ").SetBorder(true).SetTitleAlign(tview.AlignLeft)
+
+	// Action buttons
+	btnFlex := tview.NewFlex()
+	btnNew := tview.NewButton("New Relationship [n]").SetSelectedFunc(func() {
+		se.showNewRelationshipDialog(schemaIndex, tableIndex)
+	})
+	btnEdit := tview.NewButton("Edit [e]").SetSelectedFunc(func() {
+		row, _ := relTable.GetSelection()
+		if row > 0 && row <= len(relNames) {
+			relName := relNames[row-1]
+			se.showEditRelationshipDialog(schemaIndex, tableIndex, relName)
+		}
+	})
+	btnDelete := tview.NewButton("Delete [d]").SetSelectedFunc(func() {
+		row, _ := relTable.GetSelection()
+		if row > 0 && row <= len(relNames) {
+			relName := relNames[row-1]
+			se.showDeleteRelationshipConfirm(schemaIndex, tableIndex, relName)
+		}
+	})
+	btnBack := tview.NewButton("Back [b]").SetSelectedFunc(func() {
+		se.pages.RemovePage("relationships")
+		se.pages.SwitchToPage("table-editor")
+	})
+
+	// Set up button navigation
+	btnNew.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyBacktab {
+			se.app.SetFocus(relTable)
+			return nil
+		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(btnEdit)
+			return nil
+		}
+		return event
+	})
+
+	btnEdit.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyBacktab {
+			se.app.SetFocus(btnNew)
+			return nil
+		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(btnDelete)
+			return nil
+		}
+		return event
+	})
+
+	btnDelete.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyBacktab {
+			se.app.SetFocus(btnEdit)
+			return nil
+		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(btnBack)
+			return nil
+		}
+		return event
+	})
+
+	btnBack.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyBacktab {
+			se.app.SetFocus(btnDelete)
+			return nil
+		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(relTable)
+			return nil
+		}
+		return event
+	})
+
+	btnFlex.AddItem(btnNew, 0, 1, true).
+		AddItem(btnEdit, 0, 1, false).
+		AddItem(btnDelete, 0, 1, false).
+		AddItem(btnBack, 0, 1, false)
+
+	relTable.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyEscape {
+			se.pages.RemovePage("relationships")
+			se.pages.SwitchToPage("table-editor")
+			return nil
+		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(btnNew)
+			return nil
+		}
+		if event.Key() == tcell.KeyEnter {
+			row, _ := relTable.GetSelection()
+			if row > 0 && row <= len(relNames) {
+				relName := relNames[row-1]
+				se.showEditRelationshipDialog(schemaIndex, tableIndex, relName)
+			}
+			return nil
+		}
+		if event.Rune() == 'n' {
+			se.showNewRelationshipDialog(schemaIndex, tableIndex)
+			return nil
+		}
+		if event.Rune() == 'e' {
+			row, _ := relTable.GetSelection()
+			if row > 0 && row <= len(relNames) {
+				relName := relNames[row-1]
+				se.showEditRelationshipDialog(schemaIndex, tableIndex, relName)
+			}
+			return nil
+		}
+		if event.Rune() == 'd' {
+			row, _ := relTable.GetSelection()
+			if row > 0 && row <= len(relNames) {
+				relName := relNames[row-1]
+				se.showDeleteRelationshipConfirm(schemaIndex, tableIndex, relName)
+			}
+			return nil
+		}
+		if event.Rune() == 'b' {
+			se.pages.RemovePage("relationships")
+			se.pages.SwitchToPage("table-editor")
+			return nil
+		}
+		return event
+	})
+
+	flex.AddItem(title, 1, 0, false).
+		AddItem(relTable, 0, 1, true).
+		AddItem(btnFlex, 1, 0, false)
+
+	se.pages.AddPage("relationships", flex, true, true)
+}
+
+// showNewRelationshipDialog shows dialog to create a new relationship
+func (se *SchemaEditor) showNewRelationshipDialog(schemaIndex, tableIndex int) {
+	table := se.GetTable(schemaIndex, tableIndex)
+	if table == nil {
+		return
+	}
+
+	form := tview.NewForm()
+
+	// Collect all tables for dropdown
+	var allTables []string
+	var tableMap []struct{ schemaIdx, tableIdx int }
+	for si, schema := range se.db.Schemas {
+		for ti, t := range schema.Tables {
+			tableName := t.Name
+			if schema.Name != table.Schema {
+				tableName = schema.Name + "." + t.Name
+			}
+			allTables = append(allTables, tableName)
+			tableMap = append(tableMap, struct{ schemaIdx, tableIdx int }{si, ti})
+		}
+	}
+
+	relName := ""
+	relType := models.OneToMany
+	fromColumns := ""
+	toColumns := ""
+	description := ""
+	selectedTableIdx := 0
+
+	form.AddInputField("Name", "", 40, nil, func(value string) {
+		relName = value
+	})
+
+	form.AddDropDown("Type", []string{
+		string(models.OneToOne),
+		string(models.OneToMany),
+		string(models.ManyToMany),
+	}, 1, func(option string, optionIndex int) {
+		relType = models.RelationType(option)
+	})
+
+	form.AddInputField("From Columns (comma-separated)", "", 40, nil, func(value string) {
+		fromColumns = value
+	})
+
+	form.AddDropDown("To Table", allTables, 0, func(option string, optionIndex int) {
+		selectedTableIdx = optionIndex
+	})
+
+	form.AddInputField("To Columns (comma-separated)", "", 40, nil, func(value string) {
+		toColumns = value
+	})
+
+	form.AddInputField("Description", "", 60, nil, func(value string) {
+		description = value
+	})
+
+	form.AddButton("Save", func() {
+		if relName == "" {
+			return
+		}
+
+		// Parse columns
+		fromCols := strings.Split(fromColumns, ",")
+		for i := range fromCols {
+			fromCols[i] = strings.TrimSpace(fromCols[i])
+		}
+
+		toCols := strings.Split(toColumns, ",")
+		for i := range toCols {
+			toCols[i] = strings.TrimSpace(toCols[i])
+		}
+
+		// Get target table
+		targetSchema := se.db.Schemas[tableMap[selectedTableIdx].schemaIdx]
+		targetTable := targetSchema.Tables[tableMap[selectedTableIdx].tableIdx]
+
+		rel := models.InitRelationship(relName, relType)
+		rel.FromTable = table.Name
+		rel.FromSchema = table.Schema
+		rel.FromColumns = fromCols
+		rel.ToTable = targetTable.Name
+		rel.ToSchema = targetTable.Schema
+		rel.ToColumns = toCols
+		rel.Description = description
+
+		se.CreateRelationship(schemaIndex, tableIndex, rel)
+
+		se.pages.RemovePage("new-relationship")
+		se.pages.RemovePage("relationships")
+		se.showRelationshipList(schemaIndex, tableIndex)
+	})
+
+	form.AddButton("Back", func() {
+		se.pages.RemovePage("new-relationship")
+	})
+
+	form.SetBorder(true).SetTitle(" New Relationship ").SetTitleAlign(tview.AlignLeft)
+	form.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyEscape {
+			se.pages.RemovePage("new-relationship")
+			return nil
+		}
+		return event
+	})
+
+	se.pages.AddPage("new-relationship", form, true, true)
+}
+
+// showEditRelationshipDialog shows dialog to edit a relationship
+func (se *SchemaEditor) showEditRelationshipDialog(schemaIndex, tableIndex int, relName string) {
+	table := se.GetTable(schemaIndex, tableIndex)
+	if table == nil {
+		return
+	}
+
+	rel := se.GetRelationship(schemaIndex, tableIndex, relName)
+	if rel == nil {
+		return
+	}
+
+	form := tview.NewForm()
+
+	// Collect all tables for dropdown
+	var allTables []string
+	var tableMap []struct{ schemaIdx, tableIdx int }
+	selectedTableIdx := 0
+	for si, schema := range se.db.Schemas {
+		for ti, t := range schema.Tables {
+			tableName := t.Name
+			if schema.Name != table.Schema {
+				tableName = schema.Name + "." + t.Name
+			}
+			allTables = append(allTables, tableName)
+			tableMap = append(tableMap, struct{ schemaIdx, tableIdx int }{si, ti})
+
+			// Check if this is the current target table
+			if t.Name == rel.ToTable && schema.Name == rel.ToSchema {
+				selectedTableIdx = len(allTables) - 1
+			}
+		}
+	}
+
+	newName := rel.Name
+	relType := rel.Type
+	fromColumns := strings.Join(rel.FromColumns, ", ")
+	toColumns := strings.Join(rel.ToColumns, ", ")
+	description := rel.Description
+
+	form.AddInputField("Name", rel.Name, 40, nil, func(value string) {
+		newName = value
+	})
+
+	// Find initial type index
+	typeIdx := 1 // OneToMany default
+	typeOptions := []string{
+		string(models.OneToOne),
+		string(models.OneToMany),
+		string(models.ManyToMany),
+	}
+	for i, opt := range typeOptions {
+		if opt == string(rel.Type) {
+			typeIdx = i
+			break
+		}
+	}
+
+	form.AddDropDown("Type", typeOptions, typeIdx, func(option string, optionIndex int) {
+		relType = models.RelationType(option)
+	})
+
+	form.AddInputField("From Columns (comma-separated)", fromColumns, 40, nil, func(value string) {
+		fromColumns = value
+	})
+
+	form.AddDropDown("To Table", allTables, selectedTableIdx, func(option string, optionIndex int) {
+		selectedTableIdx = optionIndex
+	})
+
+	form.AddInputField("To Columns (comma-separated)", toColumns, 40, nil, func(value string) {
+		toColumns = value
+	})
+
+	form.AddInputField("Description", rel.Description, 60, nil, func(value string) {
+		description = value
+	})
+
+	form.AddButton("Save", func() {
+		if newName == "" {
+			return
+		}
+
+		// Parse columns
+		fromCols := strings.Split(fromColumns, ",")
+		for i := range fromCols {
+			fromCols[i] = strings.TrimSpace(fromCols[i])
+		}
+
+		toCols := strings.Split(toColumns, ",")
+		for i := range toCols {
+			toCols[i] = strings.TrimSpace(toCols[i])
+		}
+
+		// Get target table
+		targetSchema := se.db.Schemas[tableMap[selectedTableIdx].schemaIdx]
+		targetTable := targetSchema.Tables[tableMap[selectedTableIdx].tableIdx]
+
+		updatedRel := models.InitRelationship(newName, relType)
+		updatedRel.FromTable = table.Name
+		updatedRel.FromSchema = table.Schema
+		updatedRel.FromColumns = fromCols
+		updatedRel.ToTable = targetTable.Name
+		updatedRel.ToSchema = targetTable.Schema
+		updatedRel.ToColumns = toCols
+		updatedRel.Description = description
+		updatedRel.GUID = rel.GUID
+
+		se.UpdateRelationship(schemaIndex, tableIndex, relName, updatedRel)
+
+		se.pages.RemovePage("edit-relationship")
+		se.pages.RemovePage("relationships")
+		se.showRelationshipList(schemaIndex, tableIndex)
+	})
+
+	form.AddButton("Back", func() {
+		se.pages.RemovePage("edit-relationship")
+	})
+
+	form.SetBorder(true).SetTitle(" Edit Relationship ").SetTitleAlign(tview.AlignLeft)
+	form.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyEscape {
+			se.pages.RemovePage("edit-relationship")
+			return nil
+		}
+		return event
+	})
+
+	se.pages.AddPage("edit-relationship", form, true, true)
+}
+
+// showDeleteRelationshipConfirm shows confirmation dialog for deleting a relationship
+func (se *SchemaEditor) showDeleteRelationshipConfirm(schemaIndex, tableIndex int, relName string) {
+	modal := tview.NewModal().
+		SetText(fmt.Sprintf("Delete relationship '%s'? This action cannot be undone.", relName)).
+		AddButtons([]string{"Cancel", "Delete"}).
+		SetDoneFunc(func(buttonIndex int, buttonLabel string) {
+			if buttonLabel == "Delete" {
+				se.DeleteRelationship(schemaIndex, tableIndex, relName)
+				se.pages.RemovePage("delete-relationship-confirm")
+				se.pages.RemovePage("relationships")
+				se.showRelationshipList(schemaIndex, tableIndex)
+			} else {
+				se.pages.RemovePage("delete-relationship-confirm")
+			}
+		})
+
+	modal.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyEscape {
+			se.pages.RemovePage("delete-relationship-confirm")
+			return nil
+		}
+		return event
+	})
+
+	se.pages.AddAndSwitchToPage("delete-relationship-confirm", modal, true)
+}

pkg/ui/table_screens.go

@@ -270,6 +270,9 @@ func (se *SchemaEditor) showTableEditor(schemaIndex, tableIndex int, table *mode
 			se.showColumnEditor(schemaIndex, tableIndex, row-1, column)
 		}
 	})
+	btnRelations := tview.NewButton("Relations [r]").SetSelectedFunc(func() {
+		se.showRelationshipList(schemaIndex, tableIndex)
+	})
 	btnDelTable := tview.NewButton("Delete Table [d]").SetSelectedFunc(func() {
 		se.showDeleteTableConfirm(schemaIndex, tableIndex)
 	})
@@ -308,6 +311,18 @@ func (se *SchemaEditor) showTableEditor(schemaIndex, tableIndex int, table *mode
 			se.app.SetFocus(btnEditColumn)
 			return nil
 		}
+		if event.Key() == tcell.KeyTab {
+			se.app.SetFocus(btnRelations)
+			return nil
+		}
+		return event
+	})
+
+	btnRelations.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
+		if event.Key() == tcell.KeyBacktab {
+			se.app.SetFocus(btnEditTable)
+			return nil
+		}
 		if event.Key() == tcell.KeyTab {
 			se.app.SetFocus(btnDelTable)
 			return nil
@@ -317,7 +332,7 @@ func (se *SchemaEditor) showTableEditor(schemaIndex, tableIndex int, table *mode
 
 	btnDelTable.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
 		if event.Key() == tcell.KeyBacktab {
-			se.app.SetFocus(btnEditTable)
+			se.app.SetFocus(btnRelations)
 			return nil
 		}
 		if event.Key() == tcell.KeyTab {
@@ -342,6 +357,7 @@ func (se *SchemaEditor) showTableEditor(schemaIndex, tableIndex int, table *mode
 	btnFlex.AddItem(btnNewCol, 0, 1, true).
 		AddItem(btnEditColumn, 0, 1, false).
 		AddItem(btnEditTable, 0, 1, false).
+		AddItem(btnRelations, 0, 1, false).
 		AddItem(btnDelTable, 0, 1, false).
 		AddItem(btnBack, 0, 1, false)
 
@@ -373,6 +389,10 @@ func (se *SchemaEditor) showTableEditor(schemaIndex, tableIndex int, table *mode
 			}
 			return nil
 		}
+		if event.Rune() == 'r' {
+			se.showRelationshipList(schemaIndex, tableIndex)
+			return nil
+		}
 		if event.Rune() == 'b' {
 			se.pages.RemovePage("table-editor")
 			se.pages.SwitchToPage("schema-editor")

pkg/writers/bun/template_data.go

@@ -106,11 +106,8 @@ func (td *TemplateData) FinalizeImports() {
 }
 
 // NewModelData creates a new ModelData from a models.Table
-func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper) *ModelData {
-	tableName := table.Name
-	if schema != "" {
-		tableName = schema + "." + table.Name
-	}
+func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper, flattenSchema bool) *ModelData {
+	tableName := writers.QualifiedTableName(schema, table.Name, flattenSchema)
 
 	// Generate model name: Model + Schema + Table (all PascalCase)
 	singularTable := Singularize(table.Name)

pkg/writers/bun/writer.go

@@ -86,7 +86,7 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 	// Collect all models
 	for _, schema := range db.Schemas {
 		for _, table := range schema.Tables {
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)
@@ -181,7 +181,7 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 			templateData.AddImport(fmt.Sprintf("resolvespec_common \"%s\"", w.typeMapper.GetSQLTypesImport()))
 
 			// Create model data
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)

pkg/writers/doc.go

@@ -0,0 +1,67 @@
+// Package writers provides interfaces and implementations for writing database schemas
+// to various output formats and destinations.
+//
+// # Overview
+//
+// The writers package defines a common Writer interface that all format-specific writers
+// implement. This allows RelSpec to export database schemas to multiple formats including:
+//   - SQL schema files (PostgreSQL, SQLite)
+//   - Schema definition files (DBML, DCTX, DrawDB, GraphQL)
+//   - ORM model files (GORM, Bun, Drizzle, Prisma, TypeORM)
+//   - Data interchange formats (JSON, YAML)
+//
+// # Architecture
+//
+// Each writer implementation is located in its own subpackage (e.g., pkg/writers/dbml,
+// pkg/writers/pgsql) and implements the Writer interface, supporting three levels of
+// granularity:
+//   - WriteDatabase() - Write complete database with all schemas
+//   - WriteSchema() - Write single schema with all tables
+//   - WriteTable() - Write single table with all columns and metadata
+//
+// # Usage
+//
+// Writers are instantiated with WriterOptions containing destination-specific configuration:
+//
+//	// Write to file
+//	writer := dbml.NewWriter(&writers.WriterOptions{
+//	    OutputPath: "schema.dbml",
+//	})
+//	err := writer.WriteDatabase(db)
+//
+//	// Write ORM models with package name
+//	writer := gorm.NewWriter(&writers.WriterOptions{
+//	    OutputPath:  "./models",
+//	    PackageName: "models",
+//	})
+//	err := writer.WriteDatabase(db)
+//
+//	// Write with schema flattening for SQLite
+//	writer := sqlite.NewWriter(&writers.WriterOptions{
+//	    OutputPath:    "schema.sql",
+//	    FlattenSchema: true,
+//	})
+//	err := writer.WriteDatabase(db)
+//
+// # Schema Flattening
+//
+// The FlattenSchema option controls how schema-qualified table names are handled:
+//   - false (default): Uses dot notation (schema.table)
+//   - true: Joins with underscore (schema_table), useful for SQLite
+//
+// # Supported Formats
+//
+//   - dbml: Database Markup Language files
+//   - dctx: DCTX schema files
+//   - drawdb: DrawDB JSON format
+//   - graphql: GraphQL schema definition language
+//   - json: JSON database schema
+//   - yaml: YAML database schema
+//   - gorm: Go GORM model structs
+//   - bun: Go Bun model structs
+//   - drizzle: TypeScript Drizzle ORM schemas
+//   - prisma: Prisma schema language
+//   - typeorm: TypeScript TypeORM entities
+//   - pgsql: PostgreSQL SQL schema
+//   - sqlite: SQLite SQL schema with automatic flattening
+package writers

pkg/writers/gorm/template_data.go

@@ -105,11 +105,8 @@ func (td *TemplateData) FinalizeImports() {
 }
 
 // NewModelData creates a new ModelData from a models.Table
-func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper) *ModelData {
-	tableName := table.Name
-	if schema != "" {
-		tableName = schema + "." + table.Name
-	}
+func NewModelData(table *models.Table, schema string, typeMapper *TypeMapper, flattenSchema bool) *ModelData {
+	tableName := writers.QualifiedTableName(schema, table.Name, flattenSchema)
 
 	// Generate model name: Model + Schema + Table (all PascalCase)
 	singularTable := Singularize(table.Name)

pkg/writers/gorm/writer.go

@@ -83,7 +83,7 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 	// Collect all models
 	for _, schema := range db.Schemas {
 		for _, table := range schema.Tables {
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)
@@ -175,7 +175,7 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 			templateData.AddImport(fmt.Sprintf("sql_types \"%s\"", w.typeMapper.GetSQLTypesImport()))
 
 			// Create model data
-			modelData := NewModelData(table, schema.Name, w.typeMapper)
+			modelData := NewModelData(table, schema.Name, w.typeMapper, w.options.FlattenSchema)
 
 			// Add relationship fields
 			w.addRelationshipFields(modelData, table, schema, db)

pkg/writers/pgsql/migration_writer.go

@@ -31,7 +31,7 @@ type MigrationWriter struct {
 
 // NewMigrationWriter creates a new templated migration writer
 func NewMigrationWriter(options *writers.WriterOptions) (*MigrationWriter, error) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(options.FlattenSchema)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create template executor: %w", err)
 	}

pkg/writers/pgsql/migration_writer_test.go

@@ -137,7 +137,7 @@ func TestWriteMigration_WithAudit(t *testing.T) {
 }
 
 func TestTemplateExecutor_CreateTable(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}
@@ -170,7 +170,7 @@ func TestTemplateExecutor_CreateTable(t *testing.T) {
 }
 
 func TestTemplateExecutor_AuditFunction(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}
@@ -215,3 +215,70 @@ func TestTemplateExecutor_AuditFunction(t *testing.T) {
 		t.Error("SQL missing DELETE handling")
 	}
 }
+
+func TestWriteMigration_NumericConstraintNames(t *testing.T) {
+	// Current database (empty)
+	current := models.InitDatabase("testdb")
+	currentSchema := models.InitSchema("entity")
+	current.Schemas = append(current.Schemas, currentSchema)
+
+	// Model database (with constraint starting with number)
+	model := models.InitDatabase("testdb")
+	modelSchema := models.InitSchema("entity")
+
+	// Create individual_actor_relationship table
+	table := models.InitTable("individual_actor_relationship", "entity")
+	idCol := models.InitColumn("id", "individual_actor_relationship", "entity")
+	idCol.Type = "integer"
+	idCol.IsPrimaryKey = true
+	table.Columns["id"] = idCol
+
+	actorIDCol := models.InitColumn("actor_id", "individual_actor_relationship", "entity")
+	actorIDCol.Type = "integer"
+	table.Columns["actor_id"] = actorIDCol
+
+	// Add constraint with name starting with number
+	constraint := &models.Constraint{
+		Name:              "215162_fk_actor",
+		Type:              models.ForeignKeyConstraint,
+		Columns:           []string{"actor_id"},
+		ReferencedSchema:  "entity",
+		ReferencedTable:   "actor",
+		ReferencedColumns: []string{"id"},
+		OnDelete:          "CASCADE",
+		OnUpdate:          "NO ACTION",
+	}
+	table.Constraints["215162_fk_actor"] = constraint
+
+	modelSchema.Tables = append(modelSchema.Tables, table)
+	model.Schemas = append(model.Schemas, modelSchema)
+
+	// Generate migration
+	var buf bytes.Buffer
+	writer, err := NewMigrationWriter(&writers.WriterOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create writer: %v", err)
+	}
+	writer.writer = &buf
+
+	err = writer.WriteMigration(model, current)
+	if err != nil {
+		t.Fatalf("WriteMigration failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated migration:\n%s", output)
+
+	// Verify constraint name is properly quoted
+	if !strings.Contains(output, `"215162_fk_actor"`) {
+		t.Error("Constraint name starting with number should be quoted")
+	}
+
+	// Verify the SQL is syntactically correct (contains required keywords)
+	if !strings.Contains(output, "ADD CONSTRAINT") {
+		t.Error("Migration missing ADD CONSTRAINT")
+	}
+	if !strings.Contains(output, "FOREIGN KEY") {
+		t.Error("Migration missing FOREIGN KEY")
+	}
+}

pkg/writers/pgsql/template_functions.go

@@ -21,6 +21,7 @@ func TemplateFunctions() map[string]interface{} {
 		"quote":           quote,
 		"escape":          escape,
 		"safe_identifier": safeIdentifier,
+		"quote_ident":     quoteIdent,
 
 		// Type conversion
 		"goTypeToSQL": goTypeToSQL,
@@ -122,6 +123,43 @@ func safeIdentifier(s string) string {
 	return strings.ToLower(safe)
 }
 
+// quoteIdent quotes a PostgreSQL identifier if necessary
+// Identifiers need quoting if they:
+// - Start with a digit
+// - Contain special characters
+// - Are reserved keywords
+// - Contain uppercase letters (to preserve case)
+func quoteIdent(s string) string {
+	if s == "" {
+		return `""`
+	}
+
+	// Check if quoting is needed
+	needsQuoting := unicode.IsDigit(rune(s[0]))
+
+	// Starts with digit
+
+	// Contains uppercase letters or special characters
+	for _, r := range s {
+		if unicode.IsUpper(r) {
+			needsQuoting = true
+			break
+		}
+		if !unicode.IsLetter(r) && !unicode.IsDigit(r) && r != '_' {
+			needsQuoting = true
+			break
+		}
+	}
+
+	if needsQuoting {
+		// Escape double quotes by doubling them
+		escaped := strings.ReplaceAll(s, `"`, `""`)
+		return `"` + escaped + `"`
+	}
+
+	return s
+}
+
 // Type conversion functions
 
 // goTypeToSQL converts Go type to PostgreSQL type

pkg/writers/pgsql/template_functions_test.go

@@ -101,6 +101,31 @@ func TestSafeIdentifier(t *testing.T) {
 	}
 }
 
+func TestQuoteIdent(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"valid_name", "valid_name"},
+		{"ValidName", `"ValidName"`},
+		{"123column", `"123column"`},
+		{"215162_fk_constraint", `"215162_fk_constraint"`},
+		{"user-id", `"user-id"`},
+		{"user@domain", `"user@domain"`},
+		{`"quoted"`, `"""quoted"""`},
+		{"", `""`},
+		{"lowercase", "lowercase"},
+		{"with_underscore", "with_underscore"},
+	}
+
+	for _, tt := range tests {
+		result := quoteIdent(tt.input)
+		if result != tt.expected {
+			t.Errorf("quoteIdent(%q) = %q, want %q", tt.input, result, tt.expected)
+		}
+	}
+}
+
 func TestGoTypeToSQL(t *testing.T) {
 	tests := []struct {
 		input    string
@@ -243,7 +268,7 @@ func TestTemplateFunctions(t *testing.T) {
 	// Check that all expected functions are registered
 	expectedFuncs := []string{
 		"upper", "lower", "snake_case", "camelCase",
-		"indent", "quote", "escape", "safe_identifier",
+		"indent", "quote", "escape", "safe_identifier", "quote_ident",
 		"goTypeToSQL", "sqlTypeToGo", "isNumeric", "isText",
 		"first", "last", "filter", "mapFunc", "join_with",
 		"join",
@@ -289,7 +314,7 @@ func TestFormatType(t *testing.T) {
 
 // Test that template functions work in actual templates
 func TestTemplateFunctionsInTemplate(t *testing.T) {
-	executor, err := NewTemplateExecutor()
+	executor, err := NewTemplateExecutor(false)
 	if err != nil {
 		t.Fatalf("Failed to create executor: %v", err)
 	}

pkg/writers/pgsql/templates.go

@@ -18,14 +18,39 @@ type TemplateExecutor struct {
 	templates *template.Template
 }
 
-// NewTemplateExecutor creates a new template executor
-func NewTemplateExecutor() (*TemplateExecutor, error) {
+// NewTemplateExecutor creates a new template executor.
+// flattenSchema controls whether schema.table identifiers use dot or underscore separation.
+func NewTemplateExecutor(flattenSchema bool) (*TemplateExecutor, error) {
 	// Create template with custom functions
 	funcMap := make(template.FuncMap)
 	for k, v := range TemplateFunctions() {
 		funcMap[k] = v
 	}
 
+	// qual_table returns a quoted, schema-qualified identifier.
+	// With flatten=false: "schema"."table" (or unquoted equivalents).
+	// With flatten=true:  "schema_table".
+	funcMap["qual_table"] = func(schema, name string) string {
+		if schema == "" {
+			return quoteIdent(name)
+		}
+		if flattenSchema {
+			return quoteIdent(schema + "_" + name)
+		}
+		return quoteIdent(schema) + "." + quoteIdent(name)
+	}
+
+	// qual_table_raw is the same as qual_table but without identifier quoting.
+	funcMap["qual_table_raw"] = func(schema, name string) string {
+		if schema == "" {
+			return name
+		}
+		if flattenSchema {
+			return schema + "_" + name
+		}
+		return schema + "." + name
+	}
+
 	tmpl, err := template.New("").Funcs(funcMap).ParseFS(templateFS, "templates/*.tmpl")
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse templates: %w", err)
@@ -177,6 +202,72 @@ type AuditTriggerData struct {
 	Events       string
 }
 
+// CreateUniqueConstraintData contains data for create unique constraint template
+type CreateUniqueConstraintData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	Columns        string
+}
+
+// CreateCheckConstraintData contains data for create check constraint template
+type CreateCheckConstraintData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	Expression     string
+}
+
+// CreateForeignKeyWithCheckData contains data for create foreign key with existence check template
+type CreateForeignKeyWithCheckData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	SourceColumns  string
+	TargetSchema   string
+	TargetTable    string
+	TargetColumns  string
+	OnDelete       string
+	OnUpdate       string
+	Deferrable     bool
+}
+
+// SetSequenceValueData contains data for set sequence value template
+type SetSequenceValueData struct {
+	SchemaName   string
+	TableName    string
+	SequenceName string
+	ColumnName   string
+}
+
+// CreateSequenceData contains data for create sequence template
+type CreateSequenceData struct {
+	SchemaName   string
+	SequenceName string
+	Increment    int
+	MinValue     int64
+	MaxValue     int64
+	StartValue   int64
+	CacheSize    int
+}
+
+// AddColumnWithCheckData contains data for add column with existence check template
+type AddColumnWithCheckData struct {
+	SchemaName       string
+	TableName        string
+	ColumnName       string
+	ColumnDefinition string
+}
+
+// CreatePrimaryKeyWithAutoGenCheckData contains data for primary key with auto-generated key check template
+type CreatePrimaryKeyWithAutoGenCheckData struct {
+	SchemaName     string
+	TableName      string
+	ConstraintName string
+	AutoGenNames   string // Comma-separated list of names like "'name1', 'name2'"
+	Columns        string
+}
+
 // Execute methods for each template
 
 // ExecuteCreateTable executes the create table template
@@ -319,6 +410,76 @@ func (te *TemplateExecutor) ExecuteAuditTrigger(data AuditTriggerData) (string,
 	return buf.String(), nil
 }
 
+// ExecuteCreateUniqueConstraint executes the create unique constraint template
+func (te *TemplateExecutor) ExecuteCreateUniqueConstraint(data CreateUniqueConstraintData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_unique_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_unique_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateCheckConstraint executes the create check constraint template
+func (te *TemplateExecutor) ExecuteCreateCheckConstraint(data CreateCheckConstraintData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_check_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_check_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateForeignKeyWithCheck executes the create foreign key with check template
+func (te *TemplateExecutor) ExecuteCreateForeignKeyWithCheck(data CreateForeignKeyWithCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_foreign_key_with_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_foreign_key_with_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteSetSequenceValue executes the set sequence value template
+func (te *TemplateExecutor) ExecuteSetSequenceValue(data SetSequenceValueData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "set_sequence_value.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute set_sequence_value template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateSequence executes the create sequence template
+func (te *TemplateExecutor) ExecuteCreateSequence(data CreateSequenceData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_sequence.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_sequence template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteAddColumnWithCheck executes the add column with check template
+func (te *TemplateExecutor) ExecuteAddColumnWithCheck(data AddColumnWithCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "add_column_with_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute add_column_with_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreatePrimaryKeyWithAutoGenCheck executes the create primary key with auto-generated key check template
+func (te *TemplateExecutor) ExecuteCreatePrimaryKeyWithAutoGenCheck(data CreatePrimaryKeyWithAutoGenCheckData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_primary_key_with_autogen_check.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_primary_key_with_autogen_check template: %w", err)
+	}
+	return buf.String(), nil
+}
+
 // Helper functions to build template data from models
 
 // BuildCreateTableData builds CreateTableData from a models.Table

pkg/writers/pgsql/templates/add_column.tmpl

@@ -1,4 +1,4 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ADD COLUMN IF NOT EXISTS {{.ColumnName}} {{.ColumnType}}
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  ADD COLUMN IF NOT EXISTS {{quote_ident .ColumnName}} {{.ColumnType}}
 {{- if .Default}} DEFAULT {{.Default}}{{end}}
 {{- if .NotNull}} NOT NULL{{end}};

pkg/writers/pgsql/templates/add_column_with_check.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND column_name = '{{.ColumnName}}'
+  ) THEN
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD COLUMN {{.ColumnDefinition}};
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/alter_column_default.tmpl

@@ -1,7 +1,7 @@
 {{- if .SetDefault -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} SET DEFAULT {{.DefaultValue}};
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} SET DEFAULT {{.DefaultValue}};
 {{- else -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} DROP DEFAULT;
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} DROP DEFAULT;
 {{- end -}}

pkg/writers/pgsql/templates/alter_column_type.tmpl

@@ -1,2 +1,2 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ALTER COLUMN {{.ColumnName}} TYPE {{.NewType}};
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  ALTER COLUMN {{quote_ident .ColumnName}} TYPE {{.NewType}};

pkg/writers/pgsql/templates/audit_function.tmpl

@@ -1,4 +1,4 @@
-CREATE OR REPLACE FUNCTION {{.SchemaName}}.{{.FunctionName}}()
+CREATE OR REPLACE FUNCTION {{qual_table_raw .SchemaName .FunctionName}}()
 RETURNS trigger AS
 $body$
 DECLARE
@@ -81,4 +81,4 @@ LANGUAGE plpgsql
 VOLATILE
 SECURITY DEFINER;
 
-COMMENT ON FUNCTION {{.SchemaName}}.{{.FunctionName}}() IS 'Audit trigger function for table {{.SchemaName}}.{{.TableName}}';
+COMMENT ON FUNCTION {{qual_table_raw .SchemaName .FunctionName}}() IS 'Audit trigger function for table {{qual_table_raw .SchemaName .TableName}}';

pkg/writers/pgsql/templates/audit_trigger.tmpl

@@ -4,13 +4,13 @@ BEGIN
         SELECT 1
         FROM pg_trigger
         WHERE tgname = '{{.TriggerName}}'
-        AND tgrelid = '{{.SchemaName}}.{{.TableName}}'::regclass
+        AND tgrelid = '{{qual_table_raw .SchemaName .TableName}}'::regclass
     ) THEN
         CREATE TRIGGER {{.TriggerName}}
         AFTER {{.Events}}
-        ON {{.SchemaName}}.{{.TableName}}
+        ON {{qual_table_raw .SchemaName .TableName}}
         FOR EACH ROW
-        EXECUTE FUNCTION {{.SchemaName}}.{{.FunctionName}}();
+        EXECUTE FUNCTION {{qual_table_raw .SchemaName .FunctionName}}();
     END IF;
 END;
 $$;

pkg/writers/pgsql/templates/base_constraint.tmpl

@@ -1,6 +1,6 @@
 {{/* Base constraint template */}}
 {{- define "constraint_base" -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
+ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
   ADD CONSTRAINT {{.ConstraintName}}
   {{block "constraint_definition" .}}{{end}};
 {{- end -}}
@@ -15,7 +15,7 @@ BEGIN
           AND table_name = '{{.TableName}}'
           AND constraint_name = '{{.ConstraintName}}'
     ) THEN
-        ALTER TABLE {{.SchemaName}}.{{.TableName}}
+        ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
           DROP CONSTRAINT {{.ConstraintName}};
     END IF;
 END;

pkg/writers/pgsql/templates/base_ddl.tmpl

@@ -11,7 +11,7 @@
 
 {{/* Base ALTER TABLE structure */}}
 {{- define "alter_table_base" -}}
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
+ALTER TABLE {{qual_table_raw .SchemaName .TableName}}
   {{block "alter_operation" .}}{{end}};
 {{- end -}}
 
@@ -30,5 +30,5 @@ $$;
 
 {{/* Common drop pattern */}}
 {{- define "drop_if_exists" -}}
-{{block "drop_type" .}}{{end}} IF EXISTS {{.SchemaName}}.{{.ObjectName}};
+{{block "drop_type" .}}{{end}} IF EXISTS {{qual_table_raw .SchemaName .ObjectName}};
 {{- end -}}

pkg/writers/pgsql/templates/comment_column.tmpl

@@ -1 +1 @@
-COMMENT ON COLUMN {{.SchemaName}}.{{.TableName}}.{{.ColumnName}} IS '{{.Comment}}';
+COMMENT ON COLUMN {{qual_table .SchemaName .TableName}}.{{quote_ident .ColumnName}} IS '{{.Comment}}';

pkg/writers/pgsql/templates/comment_table.tmpl

@@ -1 +1 @@
-COMMENT ON TABLE {{.SchemaName}}.{{.TableName}} IS '{{.Comment}}';
+COMMENT ON TABLE {{qual_table .SchemaName .TableName}} IS '{{.Comment}}';

pkg/writers/pgsql/templates/create_check_constraint.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} CHECK ({{.Expression}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_foreign_key.tmpl

@@ -1,10 +1,10 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  DROP CONSTRAINT IF EXISTS {{.ConstraintName}};
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  DROP CONSTRAINT IF EXISTS {{quote_ident .ConstraintName}};
 
-ALTER TABLE {{.SchemaName}}.{{.TableName}}
-  ADD CONSTRAINT {{.ConstraintName}}
+ALTER TABLE {{qual_table .SchemaName .TableName}}
+  ADD CONSTRAINT {{quote_ident .ConstraintName}}
   FOREIGN KEY ({{.SourceColumns}})
-  REFERENCES {{.TargetSchema}}.{{.TargetTable}} ({{.TargetColumns}})
+  REFERENCES {{qual_table .TargetSchema .TargetTable}} ({{.TargetColumns}})
   ON DELETE {{.OnDelete}}
   ON UPDATE {{.OnUpdate}}
   DEFERRABLE;

pkg/writers/pgsql/templates/create_foreign_key_with_check.tmpl

@@ -0,0 +1,18 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{qual_table .SchemaName .TableName}}
+      ADD CONSTRAINT {{quote_ident .ConstraintName}}
+      FOREIGN KEY ({{.SourceColumns}})
+      REFERENCES {{qual_table .TargetSchema .TargetTable}} ({{.TargetColumns}})
+      ON DELETE {{.OnDelete}}
+      ON UPDATE {{.OnUpdate}}{{if .Deferrable}}
+      DEFERRABLE{{end}};
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_index.tmpl

@@ -1,2 +1,2 @@
-CREATE {{if .Unique}}UNIQUE {{end}}INDEX IF NOT EXISTS {{.IndexName}}
-  ON {{.SchemaName}}.{{.TableName}} USING {{.IndexType}} ({{.Columns}});
+CREATE {{if .Unique}}UNIQUE {{end}}INDEX IF NOT EXISTS {{quote_ident .IndexName}}
+  ON {{qual_table .SchemaName .TableName}} USING {{.IndexType}} ({{.Columns}});

pkg/writers/pgsql/templates/create_primary_key.tmpl

@@ -6,8 +6,8 @@ BEGIN
       AND table_name = '{{.TableName}}'
       AND constraint_name = '{{.ConstraintName}}'
   ) THEN
-    ALTER TABLE {{.SchemaName}}.{{.TableName}}
-      ADD CONSTRAINT {{.ConstraintName}} PRIMARY KEY ({{.Columns}});
+    ALTER TABLE {{qual_table .SchemaName .TableName}}
+      ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
   END IF;
 END;
 $$;

pkg/writers/pgsql/templates/create_primary_key_with_autogen_check.tmpl

@@ -0,0 +1,27 @@
+DO $$
+DECLARE
+  auto_pk_name text;
+BEGIN
+  -- Drop auto-generated primary key if it exists
+  SELECT constraint_name INTO auto_pk_name
+  FROM information_schema.table_constraints
+  WHERE table_schema = '{{.SchemaName}}'
+    AND table_name = '{{.TableName}}'
+    AND constraint_type = 'PRIMARY KEY'
+    AND constraint_name IN ({{.AutoGenNames}});
+
+  IF auto_pk_name IS NOT NULL THEN
+    EXECUTE 'ALTER TABLE {{qual_table .SchemaName .TableName}} DROP CONSTRAINT ' || quote_ident(auto_pk_name);
+  END IF;
+
+  -- Add named primary key if it doesn't exist
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} PRIMARY KEY ({{.Columns}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/create_sequence.tmpl

@@ -0,0 +1,6 @@
+CREATE SEQUENCE IF NOT EXISTS {{qual_table .SchemaName .SequenceName}}
+  INCREMENT {{.Increment}}
+  MINVALUE {{.MinValue}}
+  MAXVALUE {{.MaxValue}}
+  START {{.StartValue}}
+  CACHE {{.CacheSize}};

pkg/writers/pgsql/templates/create_table.tmpl

@@ -1,7 +1,7 @@
-CREATE TABLE IF NOT EXISTS {{.SchemaName}}.{{.TableName}} (
+CREATE TABLE IF NOT EXISTS {{qual_table .SchemaName .TableName}} (
 {{- range $i, $col := .Columns}}
 {{- if $i}},{{end}}
-  {{$col.Name}} {{$col.Type}}
+  {{quote_ident $col.Name}} {{$col.Type}}
 {{- if $col.Default}} DEFAULT {{$col.Default}}{{end}}
 {{- if $col.NotNull}} NOT NULL{{end}}
 {{- end}}

pkg/writers/pgsql/templates/create_unique_constraint.tmpl

@@ -0,0 +1,12 @@
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema = '{{.SchemaName}}'
+      AND table_name = '{{.TableName}}'
+      AND constraint_name = '{{.ConstraintName}}'
+  ) THEN
+    ALTER TABLE {{qual_table .SchemaName .TableName}} ADD CONSTRAINT {{quote_ident .ConstraintName}} UNIQUE ({{.Columns}});
+  END IF;
+END;
+$$;

pkg/writers/pgsql/templates/drop_constraint.tmpl

@@ -1 +1 @@
-ALTER TABLE {{.SchemaName}}.{{.TableName}} DROP CONSTRAINT IF EXISTS {{.ConstraintName}};
+ALTER TABLE {{qual_table .SchemaName .TableName}} DROP CONSTRAINT IF EXISTS {{quote_ident .ConstraintName}};

pkg/writers/pgsql/templates/drop_index.tmpl

@@ -1 +1 @@
-DROP INDEX IF EXISTS {{.SchemaName}}.{{.IndexName}} CASCADE;
+DROP INDEX IF EXISTS {{qual_table .SchemaName .IndexName}} CASCADE;

pkg/writers/pgsql/templates/fragments.tmpl

@@ -16,7 +16,7 @@
 
 {{/* Qualified table name */}}
 {{- define "qualified_table" -}}
-{{.SchemaName}}.{{.TableName}}
+{{qual_table_raw .SchemaName .TableName}}
 {{- end -}}
 
 {{/* Index method clause */}}

pkg/writers/pgsql/templates/set_sequence_value.tmpl

@@ -0,0 +1,19 @@
+DO $$
+DECLARE
+  m_cnt bigint;
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_class c
+    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
+    WHERE c.relname = '{{.SequenceName}}'
+      AND n.nspname = '{{.SchemaName}}'
+      AND c.relkind = 'S'
+  ) THEN
+    SELECT COALESCE(MAX({{quote_ident .ColumnName}}), 0) + 1
+    FROM {{qual_table .SchemaName .TableName}}
+    INTO m_cnt;
+    
+    PERFORM setval('{{qual_table_raw .SchemaName .SequenceName}}'::regclass, m_cnt);
+  END IF;
+END;
+$$;

pkg/writers/pgsql/writer.go

@@ -22,6 +22,7 @@ type Writer struct {
 	options         *writers.WriterOptions
 	writer          io.Writer
 	executionReport *ExecutionReport
+	executor        *TemplateExecutor
 }
 
 // ExecutionReport tracks the execution status of SQL statements
@@ -57,11 +58,18 @@ type ExecutionError struct {
 
 // NewWriter creates a new PostgreSQL SQL writer
 func NewWriter(options *writers.WriterOptions) *Writer {
+	executor, _ := NewTemplateExecutor(options.FlattenSchema)
 	return &Writer{
-		options: options,
+		options:  options,
+		executor: executor,
 	}
 }
 
+// qualTable returns a schema-qualified name using the writer's FlattenSchema setting.
+func (w *Writer) qualTable(schema, name string) string {
+	return writers.QualifiedTableName(schema, name, w.options.FlattenSchema)
+}
+
 // WriteDatabase writes the entire database schema as SQL
 func (w *Writer) WriteDatabase(db *models.Database) error {
 	// Check if we should execute SQL directly on a database
@@ -131,8 +139,8 @@ func (w *Writer) GenerateDatabaseStatements(db *models.Database) ([]string, erro
 func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, error) {
 	statements := []string{}
 
-	// Phase 1: Create schema
-	if schema.Name != "public" {
+	// Phase 1: Create schema (skip entirely when flattening)
+	if schema.Name != "public" && !w.options.FlattenSchema {
 		statements = append(statements, fmt.Sprintf("-- Schema: %s", schema.Name))
 		statements = append(statements, fmt.Sprintf("CREATE SCHEMA IF NOT EXISTS %s", schema.SQLName()))
 	}
@@ -154,8 +162,8 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 			continue
 		}
 
-		stmt := fmt.Sprintf("CREATE SEQUENCE IF NOT EXISTS %s.%s\n  INCREMENT 1\n  MINVALUE 1\n  MAXVALUE 9223372036854775807\n  START 1\n  CACHE 1",
-			schema.SQLName(), seqName)
+		stmt := fmt.Sprintf("CREATE SEQUENCE IF NOT EXISTS %s\n  INCREMENT 1\n  MINVALUE 1\n  MAXVALUE 9223372036854775807\n  START 1\n  CACHE 1",
+			w.qualTable(schema.SQLName(), seqName))
 		statements = append(statements, stmt)
 	}
 
@@ -168,6 +176,13 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 		statements = append(statements, stmts...)
 	}
 
+	// Phase 3.5: Add missing columns (for existing tables)
+	addColStmts, err := w.GenerateAddColumnStatements(schema)
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate add column statements: %w", err)
+	}
+	statements = append(statements, addColStmts...)
+
 	// Phase 4: Primary keys
 	for _, table := range schema.Tables {
 		// First check for explicit PrimaryKeyConstraint
@@ -208,36 +223,19 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
 			}
 
-			// Wrap in DO block to drop auto-generated PK and add our named PK
-			stmt := fmt.Sprintf("DO $$\nDECLARE\n"+
-				"  auto_pk_name text;\n"+
-				"BEGIN\n"+
-				"  -- Drop auto-generated primary key if it exists\n"+
-				"  SELECT constraint_name INTO auto_pk_name\n"+
-				"  FROM information_schema.table_constraints\n"+
-				"  WHERE table_schema = '%s'\n"+
-				"    AND table_name = '%s'\n"+
-				"    AND constraint_type = 'PRIMARY KEY'\n"+
-				"    AND constraint_name IN (%s);\n"+
-				"\n"+
-				"  IF auto_pk_name IS NOT NULL THEN\n"+
-				"    EXECUTE 'ALTER TABLE %s.%s DROP CONSTRAINT ' || quote_ident(auto_pk_name);\n"+
-				"  END IF;\n"+
-				"\n"+
-				"  -- Add named primary key if it doesn't exist\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.table_constraints\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND constraint_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD CONSTRAINT %s PRIMARY KEY (%s);\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, formatStringList(autoGenPKNames),
-				schema.SQLName(), table.SQLName(),
-				schema.Name, table.Name, pkName,
-				schema.SQLName(), table.SQLName(), pkName, strings.Join(pkColumns, ", "))
+			// Use template to generate primary key statement
+			data := CreatePrimaryKeyWithAutoGenCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: pkName,
+				AutoGenNames:   formatStringList(autoGenPKNames),
+				Columns:        strings.Join(pkColumns, ", "),
+			}
+
+			stmt, err := w.executor.ExecuteCreatePrimaryKeyWithAutoGenCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate primary key for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -282,8 +280,54 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				whereClause = fmt.Sprintf(" WHERE %s", index.Where)
 			}
 
-			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s.%s USING %s (%s)%s",
-				uniqueStr, index.Name, schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
+			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s",
+				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
+			statements = append(statements, stmt)
+		}
+	}
+
+	// Phase 5.5: Unique constraints
+	for _, table := range schema.Tables {
+		for _, constraint := range table.Constraints {
+			if constraint.Type != models.UniqueConstraint {
+				continue
+			}
+
+			// Use template to generate unique constraint statement
+			data := CreateUniqueConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Columns:        strings.Join(constraint.Columns, ", "),
+			}
+
+			stmt, err := w.executor.ExecuteCreateUniqueConstraint(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate unique constraint for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			statements = append(statements, stmt)
+		}
+	}
+
+	// Phase 5.7: Check constraints
+	for _, table := range schema.Tables {
+		for _, constraint := range table.Constraints {
+			if constraint.Type != models.CheckConstraint {
+				continue
+			}
+
+			// Use template to generate check constraint statement
+			data := CreateCheckConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Expression:     constraint.Expression,
+			}
+
+			stmt, err := w.executor.ExecuteCreateCheckConstraint(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate check constraint for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -310,23 +354,24 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				onUpdate = "NO ACTION"
 			}
 
-			// Wrap in DO block to check for existing constraint
-			stmt := fmt.Sprintf("DO $$\nBEGIN\n"+
-				"  IF NOT EXISTS (\n"+
-				"    SELECT 1 FROM information_schema.table_constraints\n"+
-				"    WHERE table_schema = '%s'\n"+
-				"      AND table_name = '%s'\n"+
-				"      AND constraint_name = '%s'\n"+
-				"  ) THEN\n"+
-				"    ALTER TABLE %s.%s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s.%s(%s) ON DELETE %s ON UPDATE %s;\n"+
-				"  END IF;\n"+
-				"END;\n$$",
-				schema.Name, table.Name, constraint.Name,
-				schema.SQLName(), table.SQLName(), constraint.Name,
-				strings.Join(constraint.Columns, ", "),
-				strings.ToLower(refSchema), strings.ToLower(constraint.ReferencedTable),
-				strings.Join(constraint.ReferencedColumns, ", "),
-				onDelete, onUpdate)
+			// Use template to generate foreign key statement
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				SourceColumns:  strings.Join(constraint.Columns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    constraint.ReferencedTable,
+				TargetColumns:  strings.Join(constraint.ReferencedColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     false,
+			}
+
+			stmt, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
 			statements = append(statements, stmt)
 		}
 	}
@@ -334,15 +379,15 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 	// Phase 7: Comments
 	for _, table := range schema.Tables {
 		if table.Comment != "" {
-			stmt := fmt.Sprintf("COMMENT ON TABLE %s.%s IS '%s'",
-				schema.SQLName(), table.SQLName(), escapeQuote(table.Comment))
+			stmt := fmt.Sprintf("COMMENT ON TABLE %s IS '%s'",
+				w.qualTable(schema.SQLName(), table.SQLName()), escapeQuote(table.Comment))
 			statements = append(statements, stmt)
 		}
 
 		for _, column := range table.Columns {
 			if column.Comment != "" {
-				stmt := fmt.Sprintf("COMMENT ON COLUMN %s.%s.%s IS '%s'",
-					schema.SQLName(), table.SQLName(), column.SQLName(), escapeQuote(column.Comment))
+				stmt := fmt.Sprintf("COMMENT ON COLUMN %s.%s IS '%s'",
+					w.qualTable(schema.SQLName(), table.SQLName()), column.SQLName(), escapeQuote(column.Comment))
 				statements = append(statements, stmt)
 			}
 		}
@@ -351,6 +396,67 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 	return statements, nil
 }
 
+// GenerateAddColumnStatements generates ALTER TABLE ADD COLUMN statements for existing tables
+// This is useful for schema evolution when new columns are added to existing tables
+func (w *Writer) GenerateAddColumnStatements(schema *models.Schema) ([]string, error) {
+	statements := []string{}
+
+	statements = append(statements, fmt.Sprintf("-- Add missing columns for schema: %s", schema.Name))
+
+	for _, table := range schema.Tables {
+		// Sort columns by sequence or name for consistent output
+		columns := make([]*models.Column, 0, len(table.Columns))
+		for _, col := range table.Columns {
+			columns = append(columns, col)
+		}
+		sort.Slice(columns, func(i, j int) bool {
+			if columns[i].Sequence != columns[j].Sequence {
+				return columns[i].Sequence < columns[j].Sequence
+			}
+			return columns[i].Name < columns[j].Name
+		})
+
+		for _, col := range columns {
+			colDef := w.generateColumnDefinition(col)
+
+			// Use template to generate add column statement
+			data := AddColumnWithCheckData{
+				SchemaName:       schema.Name,
+				TableName:        table.Name,
+				ColumnName:       col.Name,
+				ColumnDefinition: colDef,
+			}
+
+			stmt, err := w.executor.ExecuteAddColumnWithCheck(data)
+			if err != nil {
+				return nil, fmt.Errorf("failed to generate add column for %s.%s.%s: %w", schema.Name, table.Name, col.Name, err)
+			}
+			statements = append(statements, stmt)
+		}
+	}
+
+	return statements, nil
+}
+
+// GenerateAddColumnsForDatabase generates ALTER TABLE ADD COLUMN statements for the entire database
+func (w *Writer) GenerateAddColumnsForDatabase(db *models.Database) ([]string, error) {
+	statements := []string{}
+
+	statements = append(statements, "-- Add missing columns to existing tables")
+	statements = append(statements, fmt.Sprintf("-- Database: %s", db.Name))
+	statements = append(statements, "-- Generated by RelSpec")
+
+	for _, schema := range db.Schemas {
+		schemaStatements, err := w.GenerateAddColumnStatements(schema)
+		if err != nil {
+			return nil, fmt.Errorf("failed to generate add column statements for schema %s: %w", schema.Name, err)
+		}
+		statements = append(statements, schemaStatements...)
+	}
+
+	return statements, nil
+}
+
 // generateCreateTableStatement generates CREATE TABLE statement
 func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *models.Table) ([]string, error) {
 	statements := []string{}
@@ -373,8 +479,8 @@ func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *mode
 		columnDefs = append(columnDefs, "  "+def)
 	}
 
-	stmt := fmt.Sprintf("CREATE TABLE %s.%s (\n%s\n)",
-		schema.SQLName(), table.SQLName(), strings.Join(columnDefs, ",\n"))
+	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (\n%s\n)",
+		w.qualTable(schema.SQLName(), table.SQLName()), strings.Join(columnDefs, ",\n"))
 	statements = append(statements, stmt)
 
 	return statements, nil
@@ -458,6 +564,11 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		return err
 	}
 
+	// Phase 3.5: Add missing columns (priority 120)
+	if err := w.writeAddColumns(schema); err != nil {
+		return err
+	}
+
 	// Phase 4: Create primary keys (priority 160)
 	if err := w.writePrimaryKeys(schema); err != nil {
 		return err
@@ -468,6 +579,16 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		return err
 	}
 
+	// Phase 5.5: Create unique constraints (priority 185)
+	if err := w.writeUniqueConstraints(schema); err != nil {
+		return err
+	}
+
+	// Phase 5.7: Create check constraints (priority 190)
+	if err := w.writeCheckConstraints(schema); err != nil {
+		return err
+	}
+
 	// Phase 6: Create foreign key constraints (priority 195)
 	if err := w.writeForeignKeys(schema); err != nil {
 		return err
@@ -499,10 +620,47 @@ func (w *Writer) WriteTable(table *models.Table) error {
 	return w.WriteSchema(schema)
 }
 
+// WriteAddColumnStatements writes ALTER TABLE ADD COLUMN statements for a database
+// This is used for schema evolution/migration when new columns are added
+func (w *Writer) WriteAddColumnStatements(db *models.Database) error {
+	var writer io.Writer
+	var file *os.File
+	var err error
+
+	// Use existing writer if already set (for testing)
+	if w.writer != nil {
+		writer = w.writer
+	} else if w.options.OutputPath != "" {
+		// Determine output destination
+		file, err = os.Create(w.options.OutputPath)
+		if err != nil {
+			return fmt.Errorf("failed to create output file: %w", err)
+		}
+		defer file.Close()
+		writer = file
+	} else {
+		writer = os.Stdout
+	}
+
+	w.writer = writer
+
+	// Generate statements
+	statements, err := w.GenerateAddColumnsForDatabase(db)
+	if err != nil {
+		return err
+	}
+
+	// Write each statement
+	for _, stmt := range statements {
+		fmt.Fprintf(w.writer, "%s;\n\n", stmt)
+	}
+
+	return nil
+}
+
 // writeCreateSchema generates CREATE SCHEMA statement
 func (w *Writer) writeCreateSchema(schema *models.Schema) error {
-	if schema.Name == "public" {
-		// public schema exists by default
+	if schema.Name == "public" || w.options.FlattenSchema {
 		return nil
 	}
 
@@ -527,13 +685,23 @@ func (w *Writer) writeSequences(schema *models.Schema) error {
 		}
 
 		seqName := fmt.Sprintf("identity_%s_%s", table.SQLName(), pk.SQLName())
-		fmt.Fprintf(w.writer, "CREATE SEQUENCE IF NOT EXISTS %s.%s\n",
-			schema.SQLName(), seqName)
-		fmt.Fprintf(w.writer, "  INCREMENT 1\n")
-		fmt.Fprintf(w.writer, "  MINVALUE 1\n")
-		fmt.Fprintf(w.writer, "  MAXVALUE 9223372036854775807\n")
-		fmt.Fprintf(w.writer, "  START 1\n")
-		fmt.Fprintf(w.writer, "  CACHE 1;\n\n")
+
+		data := CreateSequenceData{
+			SchemaName:   schema.Name,
+			SequenceName: seqName,
+			Increment:    1,
+			MinValue:     1,
+			MaxValue:     9223372036854775807,
+			StartValue:   1,
+			CacheSize:    1,
+		}
+
+		sql, err := w.executor.ExecuteCreateSequence(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate create sequence for %s.%s: %w", schema.Name, seqName, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -544,8 +712,8 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 	fmt.Fprintf(w.writer, "-- Tables for schema: %s\n", schema.Name)
 
 	for _, table := range schema.Tables {
-		fmt.Fprintf(w.writer, "CREATE TABLE IF NOT EXISTS %s.%s (\n",
-			schema.SQLName(), table.SQLName())
+		fmt.Fprintf(w.writer, "CREATE TABLE IF NOT EXISTS %s (\n",
+			w.qualTable(schema.SQLName(), table.SQLName()))
 
 		// Write columns
 		columns := getSortedColumns(table.Columns)
@@ -564,6 +732,36 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 	return nil
 }
 
+// writeAddColumns generates ALTER TABLE ADD COLUMN statements for missing columns
+func (w *Writer) writeAddColumns(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Add missing columns for schema: %s\n", schema.Name)
+
+	for _, table := range schema.Tables {
+		// Sort columns by sequence or name for consistent output
+		columns := getSortedColumns(table.Columns)
+
+		for _, col := range columns {
+			colDef := w.generateColumnDefinition(col)
+
+			data := AddColumnWithCheckData{
+				SchemaName:       schema.Name,
+				TableName:        table.Name,
+				ColumnName:       col.Name,
+				ColumnDefinition: colDef,
+			}
+
+			sql, err := w.executor.ExecuteAddColumnWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate add column for %s.%s.%s: %w", schema.Name, table.Name, col.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
+			fmt.Fprint(w.writer, "\n")
+		}
+	}
+
+	return nil
+}
+
 // writePrimaryKeys generates ALTER TABLE statements for primary keys
 func (w *Writer) writePrimaryKeys(schema *models.Schema) error {
 	fmt.Fprintf(w.writer, "-- Primary keys for schema: %s\n", schema.Name)
@@ -611,37 +809,20 @@ func (w *Writer) writePrimaryKeys(schema *models.Schema) error {
 			fmt.Sprintf("%s_%s_pkey", schema.Name, table.Name),
 		}
 
-		fmt.Fprintf(w.writer, "DO $$\nDECLARE\n")
-		fmt.Fprintf(w.writer, "  auto_pk_name text;\nBEGIN\n")
+		data := CreatePrimaryKeyWithAutoGenCheckData{
+			SchemaName:     schema.Name,
+			TableName:      table.Name,
+			ConstraintName: pkName,
+			AutoGenNames:   formatStringList(autoGenPKNames),
+			Columns:        strings.Join(columnNames, ", "),
+		}
 
-		// Check for and drop auto-generated primary keys
-		fmt.Fprintf(w.writer, "  -- Drop auto-generated primary key if it exists\n")
-		fmt.Fprintf(w.writer, "  SELECT constraint_name INTO auto_pk_name\n")
-		fmt.Fprintf(w.writer, "  FROM information_schema.table_constraints\n")
-		fmt.Fprintf(w.writer, "  WHERE table_schema = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "    AND table_name = '%s'\n", table.Name)
-		fmt.Fprintf(w.writer, "    AND constraint_type = 'PRIMARY KEY'\n")
-		fmt.Fprintf(w.writer, "    AND constraint_name IN (%s);\n", formatStringList(autoGenPKNames))
-		fmt.Fprintf(w.writer, "\n")
-		fmt.Fprintf(w.writer, "  IF auto_pk_name IS NOT NULL THEN\n")
-		fmt.Fprintf(w.writer, "    EXECUTE 'ALTER TABLE %s.%s DROP CONSTRAINT ' || quote_ident(auto_pk_name);\n",
-			schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "\n")
-
-		// Add our named primary key if it doesn't exist
-		fmt.Fprintf(w.writer, "  -- Add named primary key if it doesn't exist\n")
-		fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-		fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-		fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-		fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", pkName)
-		fmt.Fprintf(w.writer, "  ) THEN\n")
-		fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "      ADD CONSTRAINT %s PRIMARY KEY (%s);\n",
-			pkName, strings.Join(columnNames, ", "))
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+		sql, err := w.executor.ExecuteCreatePrimaryKeyWithAutoGenCheck(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate primary key for %s.%s: %w", schema.Name, table.Name, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -716,8 +897,93 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 
 			fmt.Fprintf(w.writer, "CREATE %sINDEX IF NOT EXISTS %s\n",
 				unique, indexName)
-			fmt.Fprintf(w.writer, "  ON %s.%s USING %s (%s)%s;\n\n",
-				schema.SQLName(), table.SQLName(), indexType, strings.Join(columnExprs, ", "), whereClause)
+			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s;\n\n",
+				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
+		}
+	}
+
+	return nil
+}
+
+// writeUniqueConstraints generates ALTER TABLE statements for unique constraints
+func (w *Writer) writeUniqueConstraints(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Unique constraints for schema: %s\n", schema.Name)
+
+	for _, table := range schema.Tables {
+		// Sort constraints by name for consistent output
+		constraintNames := make([]string, 0, len(table.Constraints))
+		for name, constraint := range table.Constraints {
+			if constraint.Type == models.UniqueConstraint {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Build column list
+			columnExprs := make([]string, 0, len(constraint.Columns))
+			for _, colName := range constraint.Columns {
+				if col, ok := table.Columns[colName]; ok {
+					columnExprs = append(columnExprs, col.SQLName())
+				}
+			}
+
+			if len(columnExprs) == 0 {
+				continue
+			}
+
+			sql, err := w.executor.ExecuteCreateUniqueConstraint(CreateUniqueConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Columns:        strings.Join(columnExprs, ", "),
+			})
+			if err != nil {
+				return fmt.Errorf("failed to generate unique constraint: %w", err)
+			}
+
+			fmt.Fprintf(w.writer, "%s\n\n", sql)
+		}
+	}
+
+	return nil
+}
+
+// writeCheckConstraints generates ALTER TABLE statements for check constraints
+func (w *Writer) writeCheckConstraints(schema *models.Schema) error {
+	fmt.Fprintf(w.writer, "-- Check constraints for schema: %s\n", schema.Name)
+
+	for _, table := range schema.Tables {
+		// Sort constraints by name for consistent output
+		constraintNames := make([]string, 0, len(table.Constraints))
+		for name, constraint := range table.Constraints {
+			if constraint.Type == models.CheckConstraint {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Skip if expression is empty
+			if constraint.Expression == "" {
+				continue
+			}
+
+			sql, err := w.executor.ExecuteCreateCheckConstraint(CreateCheckConstraintData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				Expression:     constraint.Expression,
+			})
+			if err != nil {
+				return fmt.Errorf("failed to generate check constraint: %w", err)
+			}
+
+			fmt.Fprintf(w.writer, "%s\n\n", sql)
 		}
 	}
 
@@ -801,24 +1067,103 @@ func (w *Writer) writeForeignKeys(schema *models.Schema) error {
 				refTable = rel.ToTable
 			}
 
-			// Use DO block to check if constraint exists before adding
-			fmt.Fprintf(w.writer, "DO $$\nBEGIN\n")
-			fmt.Fprintf(w.writer, "  IF NOT EXISTS (\n")
-			fmt.Fprintf(w.writer, "    SELECT 1 FROM information_schema.table_constraints\n")
-			fmt.Fprintf(w.writer, "    WHERE table_schema = '%s'\n", schema.Name)
-			fmt.Fprintf(w.writer, "      AND table_name = '%s'\n", table.Name)
-			fmt.Fprintf(w.writer, "      AND constraint_name = '%s'\n", fkName)
-			fmt.Fprintf(w.writer, "  ) THEN\n")
-			fmt.Fprintf(w.writer, "    ALTER TABLE %s.%s\n", schema.SQLName(), table.SQLName())
-			fmt.Fprintf(w.writer, "      ADD CONSTRAINT %s\n", fkName)
-			fmt.Fprintf(w.writer, "      FOREIGN KEY (%s)\n", strings.Join(sourceColumns, ", "))
-			fmt.Fprintf(w.writer, "      REFERENCES %s.%s (%s)\n",
-				refSchema, refTable, strings.Join(targetColumns, ", "))
-			fmt.Fprintf(w.writer, "      ON DELETE %s\n", onDelete)
-			fmt.Fprintf(w.writer, "      ON UPDATE %s\n", onUpdate)
-			fmt.Fprintf(w.writer, "      DEFERRABLE;\n")
-			fmt.Fprintf(w.writer, "  END IF;\n")
-			fmt.Fprintf(w.writer, "END;\n$$;\n\n")
+			// Use template executor to generate foreign key with existence check
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: fkName,
+				SourceColumns:  strings.Join(sourceColumns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    refTable,
+				TargetColumns:  strings.Join(targetColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     true,
+			}
+			sql, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
+		}
+
+		// Also process any foreign key constraints that don't have a relationship
+		processedConstraints := make(map[string]bool)
+		for _, rel := range table.Relationships {
+			fkName := rel.ForeignKey
+			if fkName == "" {
+				fkName = rel.Name
+			}
+			if fkName != "" {
+				processedConstraints[fkName] = true
+			}
+		}
+
+		// Find unprocessed foreign key constraints
+		constraintNames := make([]string, 0)
+		for name, constraint := range table.Constraints {
+			if constraint.Type == models.ForeignKeyConstraint && !processedConstraints[name] {
+				constraintNames = append(constraintNames, name)
+			}
+		}
+		sort.Strings(constraintNames)
+
+		for _, name := range constraintNames {
+			constraint := table.Constraints[name]
+
+			// Build column lists
+			sourceColumns := make([]string, 0, len(constraint.Columns))
+			for _, colName := range constraint.Columns {
+				if col, ok := table.Columns[colName]; ok {
+					sourceColumns = append(sourceColumns, col.SQLName())
+				} else {
+					sourceColumns = append(sourceColumns, colName)
+				}
+			}
+
+			targetColumns := make([]string, 0, len(constraint.ReferencedColumns))
+			for _, colName := range constraint.ReferencedColumns {
+				targetColumns = append(targetColumns, strings.ToLower(colName))
+			}
+
+			if len(sourceColumns) == 0 || len(targetColumns) == 0 {
+				continue
+			}
+
+			onDelete := "NO ACTION"
+			if constraint.OnDelete != "" {
+				onDelete = strings.ToUpper(constraint.OnDelete)
+			}
+
+			onUpdate := "NO ACTION"
+			if constraint.OnUpdate != "" {
+				onUpdate = strings.ToUpper(constraint.OnUpdate)
+			}
+
+			refSchema := constraint.ReferencedSchema
+			if refSchema == "" {
+				refSchema = schema.Name
+			}
+			refTable := constraint.ReferencedTable
+
+			// Use template executor to generate foreign key with existence check
+			data := CreateForeignKeyWithCheckData{
+				SchemaName:     schema.Name,
+				TableName:      table.Name,
+				ConstraintName: constraint.Name,
+				SourceColumns:  strings.Join(sourceColumns, ", "),
+				TargetSchema:   refSchema,
+				TargetTable:    refTable,
+				TargetColumns:  strings.Join(targetColumns, ", "),
+				OnDelete:       onDelete,
+				OnUpdate:       onUpdate,
+				Deferrable:     false,
+			}
+			sql, err := w.executor.ExecuteCreateForeignKeyWithCheck(data)
+			if err != nil {
+				return fmt.Errorf("failed to generate foreign key for %s.%s: %w", schema.Name, table.Name, err)
+			}
+			fmt.Fprint(w.writer, sql)
 		}
 	}
 
@@ -837,26 +1182,19 @@ func (w *Writer) writeSetSequenceValues(schema *models.Schema) error {
 
 		seqName := fmt.Sprintf("identity_%s_%s", table.SQLName(), pk.SQLName())
 
-		fmt.Fprintf(w.writer, "DO $$\n")
-		fmt.Fprintf(w.writer, "DECLARE\n")
-		fmt.Fprintf(w.writer, "  m_cnt bigint;\n")
-		fmt.Fprintf(w.writer, "BEGIN\n")
-		fmt.Fprintf(w.writer, "  IF EXISTS (\n")
-		fmt.Fprintf(w.writer, "    SELECT 1 FROM pg_class c\n")
-		fmt.Fprintf(w.writer, "    INNER JOIN pg_namespace n ON n.oid = c.relnamespace\n")
-		fmt.Fprintf(w.writer, "    WHERE c.relname = '%s'\n", seqName)
-		fmt.Fprintf(w.writer, "      AND n.nspname = '%s'\n", schema.Name)
-		fmt.Fprintf(w.writer, "      AND c.relkind = 'S'\n")
-		fmt.Fprintf(w.writer, "  ) THEN\n")
-		fmt.Fprintf(w.writer, "    SELECT COALESCE(MAX(%s), 0) + 1\n", pk.SQLName())
-		fmt.Fprintf(w.writer, "    FROM %s.%s\n", schema.SQLName(), table.SQLName())
-		fmt.Fprintf(w.writer, "    INTO m_cnt;\n")
-		fmt.Fprintf(w.writer, "    \n")
-		fmt.Fprintf(w.writer, "    PERFORM setval('%s.%s'::regclass, m_cnt);\n",
-			schema.SQLName(), seqName)
-		fmt.Fprintf(w.writer, "  END IF;\n")
-		fmt.Fprintf(w.writer, "END;\n")
-		fmt.Fprintf(w.writer, "$$;\n\n")
+		// Use template executor to generate set sequence value statement
+		data := SetSequenceValueData{
+			SchemaName:   schema.Name,
+			TableName:    table.Name,
+			SequenceName: seqName,
+			ColumnName:   pk.Name,
+		}
+		sql, err := w.executor.ExecuteSetSequenceValue(data)
+		if err != nil {
+			return fmt.Errorf("failed to generate set sequence value for %s.%s: %w", schema.Name, table.Name, err)
+		}
+		fmt.Fprint(w.writer, sql)
+		fmt.Fprint(w.writer, "\n")
 	}
 
 	return nil
@@ -869,16 +1207,16 @@ func (w *Writer) writeComments(schema *models.Schema) error {
 	for _, table := range schema.Tables {
 		// Table comment
 		if table.Description != "" {
-			fmt.Fprintf(w.writer, "COMMENT ON TABLE %s.%s IS '%s';\n",
-				schema.SQLName(), table.SQLName(),
+			fmt.Fprintf(w.writer, "COMMENT ON TABLE %s IS '%s';\n",
+				w.qualTable(schema.SQLName(), table.SQLName()),
 				escapeQuote(table.Description))
 		}
 
 		// Column comments
 		for _, col := range getSortedColumns(table.Columns) {
 			if col.Description != "" {
-				fmt.Fprintf(w.writer, "COMMENT ON COLUMN %s.%s.%s IS '%s';\n",
-					schema.SQLName(), table.SQLName(), col.SQLName(),
+				fmt.Fprintf(w.writer, "COMMENT ON COLUMN %s.%s IS '%s';\n",
+					w.qualTable(schema.SQLName(), table.SQLName()), col.SQLName(),
 					escapeQuote(col.Description))
 			}
 		}
@@ -1076,7 +1414,8 @@ func (w *Writer) executeDatabaseSQL(db *models.Database, connString string) erro
 			continue
 		}
 
-		fmt.Fprintf(os.Stderr, "Executing statement %d/%d...\n", i+1, len(statements))
+		stmtType := detectStatementType(stmtTrimmed)
+		fmt.Fprintf(os.Stderr, "Executing statement %d/%d [%s]...\n", i+1, len(statements), stmtType)
 
 		_, execErr := conn.Exec(ctx, stmt)
 		if execErr != nil {
@@ -1210,3 +1549,94 @@ func truncateStatement(stmt string) string {
 func getCurrentTimestamp() string {
 	return time.Now().Format("2006-01-02 15:04:05")
 }
+
+// detectStatementType detects the type of SQL statement for logging
+func detectStatementType(stmt string) string {
+	upperStmt := strings.ToUpper(stmt)
+
+	// Check for DO blocks (used for conditional DDL)
+	if strings.HasPrefix(upperStmt, "DO $$") || strings.HasPrefix(upperStmt, "DO $") {
+		// Look inside the DO block for the actual operation
+		if strings.Contains(upperStmt, "ALTER TABLE") && strings.Contains(upperStmt, "ADD CONSTRAINT") {
+			if strings.Contains(upperStmt, "UNIQUE") {
+				return "ADD UNIQUE CONSTRAINT"
+			} else if strings.Contains(upperStmt, "FOREIGN KEY") {
+				return "ADD FOREIGN KEY"
+			} else if strings.Contains(upperStmt, "PRIMARY KEY") {
+				return "ADD PRIMARY KEY"
+			} else if strings.Contains(upperStmt, "CHECK") {
+				return "ADD CHECK CONSTRAINT"
+			}
+			return "ADD CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ALTER TABLE") && strings.Contains(upperStmt, "ADD COLUMN") {
+			return "ADD COLUMN"
+		}
+		if strings.Contains(upperStmt, "DROP CONSTRAINT") {
+			return "DROP CONSTRAINT"
+		}
+		return "DO BLOCK"
+	}
+
+	// Direct DDL statements
+	if strings.HasPrefix(upperStmt, "CREATE SCHEMA") {
+		return "CREATE SCHEMA"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE SEQUENCE") {
+		return "CREATE SEQUENCE"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE TABLE") {
+		return "CREATE TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE INDEX") {
+		return "CREATE INDEX"
+	}
+	if strings.HasPrefix(upperStmt, "CREATE UNIQUE INDEX") {
+		return "CREATE UNIQUE INDEX"
+	}
+	if strings.HasPrefix(upperStmt, "ALTER TABLE") {
+		if strings.Contains(upperStmt, "ADD CONSTRAINT") {
+			if strings.Contains(upperStmt, "FOREIGN KEY") {
+				return "ADD FOREIGN KEY"
+			} else if strings.Contains(upperStmt, "PRIMARY KEY") {
+				return "ADD PRIMARY KEY"
+			} else if strings.Contains(upperStmt, "UNIQUE") {
+				return "ADD UNIQUE CONSTRAINT"
+			} else if strings.Contains(upperStmt, "CHECK") {
+				return "ADD CHECK CONSTRAINT"
+			}
+			return "ADD CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ADD COLUMN") {
+			return "ADD COLUMN"
+		}
+		if strings.Contains(upperStmt, "DROP CONSTRAINT") {
+			return "DROP CONSTRAINT"
+		}
+		if strings.Contains(upperStmt, "ALTER COLUMN") {
+			return "ALTER COLUMN"
+		}
+		return "ALTER TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "COMMENT ON TABLE") {
+		return "COMMENT ON TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "COMMENT ON COLUMN") {
+		return "COMMENT ON COLUMN"
+	}
+	if strings.HasPrefix(upperStmt, "DROP TABLE") {
+		return "DROP TABLE"
+	}
+	if strings.HasPrefix(upperStmt, "DROP INDEX") {
+		return "DROP INDEX"
+	}
+
+	// Default
+	return "SQL"
+}
+
+// quoteIdentifier wraps an identifier in double quotes if necessary
+// This is needed for identifiers that start with numbers or contain special characters
+func quoteIdentifier(s string) string {
+	return quoteIdent(s)
+}

pkg/writers/pgsql/writer_test.go

@@ -164,6 +164,296 @@ func TestWriteForeignKeys(t *testing.T) {
 	}
 }
 
+func TestWriteUniqueConstraints(t *testing.T) {
+	// Create a test database with unique constraints
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create table with unique constraints
+	table := models.InitTable("users", "public")
+
+	// Add columns
+	emailCol := models.InitColumn("email", "users", "public")
+	emailCol.Type = "varchar(255)"
+	emailCol.NotNull = true
+	table.Columns["email"] = emailCol
+
+	guidCol := models.InitColumn("guid", "users", "public")
+	guidCol.Type = "uuid"
+	guidCol.NotNull = true
+	table.Columns["guid"] = guidCol
+
+	// Add unique constraints
+	emailConstraint := &models.Constraint{
+		Name:    "uq_email",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "users",
+		Columns: []string{"email"},
+	}
+	table.Constraints["uq_email"] = emailConstraint
+
+	guidConstraint := &models.Constraint{
+		Name:    "uq_guid",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "users",
+		Columns: []string{"guid"},
+	}
+	table.Constraints["uq_guid"] = guidConstraint
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify unique constraints are present
+	if !strings.Contains(output, "-- Unique constraints for schema: public") {
+		t.Errorf("Output missing unique constraints header")
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT uq_email UNIQUE (email)") {
+		t.Errorf("Output missing uq_email unique constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT uq_guid UNIQUE (guid)") {
+		t.Errorf("Output missing uq_guid unique constraint\nFull output:\n%s", output)
+	}
+}
+
+func TestWriteCheckConstraints(t *testing.T) {
+	// Create a test database with check constraints
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create table with check constraints
+	table := models.InitTable("products", "public")
+
+	// Add columns
+	priceCol := models.InitColumn("price", "products", "public")
+	priceCol.Type = "numeric(10,2)"
+	table.Columns["price"] = priceCol
+
+	statusCol := models.InitColumn("status", "products", "public")
+	statusCol.Type = "varchar(20)"
+	table.Columns["status"] = statusCol
+
+	quantityCol := models.InitColumn("quantity", "products", "public")
+	quantityCol.Type = "integer"
+	table.Columns["quantity"] = quantityCol
+
+	// Add check constraints
+	priceConstraint := &models.Constraint{
+		Name:       "ck_price_positive",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "price >= 0",
+	}
+	table.Constraints["ck_price_positive"] = priceConstraint
+
+	statusConstraint := &models.Constraint{
+		Name:       "ck_status_valid",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "status IN ('active', 'inactive', 'discontinued')",
+	}
+	table.Constraints["ck_status_valid"] = statusConstraint
+
+	quantityConstraint := &models.Constraint{
+		Name:       "ck_quantity_nonnegative",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "products",
+		Expression: "quantity >= 0",
+	}
+	table.Constraints["ck_quantity_nonnegative"] = quantityConstraint
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify check constraints are present
+	if !strings.Contains(output, "-- Check constraints for schema: public") {
+		t.Errorf("Output missing check constraints header")
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_price_positive CHECK (price >= 0)") {
+		t.Errorf("Output missing ck_price_positive check constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_status_valid CHECK (status IN ('active', 'inactive', 'discontinued'))") {
+		t.Errorf("Output missing ck_status_valid check constraint\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ADD CONSTRAINT ck_quantity_nonnegative CHECK (quantity >= 0)") {
+		t.Errorf("Output missing ck_quantity_nonnegative check constraint\nFull output:\n%s", output)
+	}
+}
+
+func TestWriteAllConstraintTypes(t *testing.T) {
+	// Create a comprehensive test with all constraint types
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create orders table
+	ordersTable := models.InitTable("orders", "public")
+
+	// Add columns
+	idCol := models.InitColumn("id", "orders", "public")
+	idCol.Type = "integer"
+	idCol.IsPrimaryKey = true
+	ordersTable.Columns["id"] = idCol
+
+	userIDCol := models.InitColumn("user_id", "orders", "public")
+	userIDCol.Type = "integer"
+	userIDCol.NotNull = true
+	ordersTable.Columns["user_id"] = userIDCol
+
+	orderNumberCol := models.InitColumn("order_number", "orders", "public")
+	orderNumberCol.Type = "varchar(50)"
+	orderNumberCol.NotNull = true
+	ordersTable.Columns["order_number"] = orderNumberCol
+
+	totalCol := models.InitColumn("total", "orders", "public")
+	totalCol.Type = "numeric(10,2)"
+	ordersTable.Columns["total"] = totalCol
+
+	statusCol := models.InitColumn("status", "orders", "public")
+	statusCol.Type = "varchar(20)"
+	ordersTable.Columns["status"] = statusCol
+
+	// Add primary key constraint
+	pkConstraint := &models.Constraint{
+		Name:    "pk_orders",
+		Type:    models.PrimaryKeyConstraint,
+		Schema:  "public",
+		Table:   "orders",
+		Columns: []string{"id"},
+	}
+	ordersTable.Constraints["pk_orders"] = pkConstraint
+
+	// Add unique constraint
+	uniqueConstraint := &models.Constraint{
+		Name:    "uq_order_number",
+		Type:    models.UniqueConstraint,
+		Schema:  "public",
+		Table:   "orders",
+		Columns: []string{"order_number"},
+	}
+	ordersTable.Constraints["uq_order_number"] = uniqueConstraint
+
+	// Add check constraint
+	checkConstraint := &models.Constraint{
+		Name:       "ck_total_positive",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "orders",
+		Expression: "total > 0",
+	}
+	ordersTable.Constraints["ck_total_positive"] = checkConstraint
+
+	statusCheckConstraint := &models.Constraint{
+		Name:       "ck_status_valid",
+		Type:       models.CheckConstraint,
+		Schema:     "public",
+		Table:      "orders",
+		Expression: "status IN ('pending', 'completed', 'cancelled')",
+	}
+	ordersTable.Constraints["ck_status_valid"] = statusCheckConstraint
+
+	// Add foreign key constraint (referencing a users table)
+	fkConstraint := &models.Constraint{
+		Name:              "fk_orders_user",
+		Type:              models.ForeignKeyConstraint,
+		Schema:            "public",
+		Table:             "orders",
+		Columns:           []string{"user_id"},
+		ReferencedSchema:  "public",
+		ReferencedTable:   "users",
+		ReferencedColumns: []string{"id"},
+		OnDelete:          "CASCADE",
+		OnUpdate:          "CASCADE",
+	}
+	ordersTable.Constraints["fk_orders_user"] = fkConstraint
+
+	schema.Tables = append(schema.Tables, ordersTable)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write the database
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Print output for debugging
+	t.Logf("Generated SQL:\n%s", output)
+
+	// Verify all constraint types are present
+	expectedConstraints := map[string]string{
+		"Primary Key":      "PRIMARY KEY",
+		"Unique":           "ADD CONSTRAINT uq_order_number UNIQUE (order_number)",
+		"Check (total)":    "ADD CONSTRAINT ck_total_positive CHECK (total > 0)",
+		"Check (status)":   "ADD CONSTRAINT ck_status_valid CHECK (status IN ('pending', 'completed', 'cancelled'))",
+		"Foreign Key":      "FOREIGN KEY",
+	}
+
+	for name, expected := range expectedConstraints {
+		if !strings.Contains(output, expected) {
+			t.Errorf("Output missing %s constraint: %s\nFull output:\n%s", name, expected, output)
+		}
+	}
+
+	// Verify section headers
+	sections := []string{
+		"-- Primary keys for schema: public",
+		"-- Unique constraints for schema: public",
+		"-- Check constraints for schema: public",
+		"-- Foreign keys for schema: public",
+	}
+
+	for _, section := range sections {
+		if !strings.Contains(output, section) {
+			t.Errorf("Output missing section header: %s", section)
+		}
+	}
+}
+
 func TestWriteTable(t *testing.T) {
 	// Create a single table
 	table := models.InitTable("products", "public")
@@ -438,3 +728,130 @@ func TestColumnSizeSpecifiers(t *testing.T) {
 		}
 	}
 }
+
+func TestGenerateAddColumnStatements(t *testing.T) {
+	// Create a test database with tables that have new columns
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create a table with columns
+	table := models.InitTable("users", "public")
+
+	// Existing column
+	idCol := models.InitColumn("id", "users", "public")
+	idCol.Type = "integer"
+	idCol.NotNull = true
+	idCol.Sequence = 1
+	table.Columns["id"] = idCol
+
+	// New column to be added
+	emailCol := models.InitColumn("email", "users", "public")
+	emailCol.Type = "varchar"
+	emailCol.Length = 255
+	emailCol.NotNull = true
+	emailCol.Sequence = 2
+	table.Columns["email"] = emailCol
+
+	// New column with default
+	statusCol := models.InitColumn("status", "users", "public")
+	statusCol.Type = "text"
+	statusCol.Default = "active"
+	statusCol.Sequence = 3
+	table.Columns["status"] = statusCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+
+	// Generate ADD COLUMN statements
+	statements, err := writer.GenerateAddColumnsForDatabase(db)
+	if err != nil {
+		t.Fatalf("GenerateAddColumnsForDatabase failed: %v", err)
+	}
+
+	// Join all statements to verify content
+	output := strings.Join(statements, "\n")
+	t.Logf("Generated ADD COLUMN statements:\n%s", output)
+
+	// Verify expected elements
+	expectedStrings := []string{
+		"ALTER TABLE public.users ADD COLUMN id integer NOT NULL",
+		"ALTER TABLE public.users ADD COLUMN email varchar(255) NOT NULL",
+		"ALTER TABLE public.users ADD COLUMN status text DEFAULT 'active'",
+		"information_schema.columns",
+		"table_schema = 'public'",
+		"table_name = 'users'",
+		"column_name = 'id'",
+		"column_name = 'email'",
+		"column_name = 'status'",
+	}
+
+	for _, expected := range expectedStrings {
+		if !strings.Contains(output, expected) {
+			t.Errorf("Output missing expected string: %s\nFull output:\n%s", expected, output)
+		}
+	}
+
+	// Verify DO blocks are present for conditional adds
+	doBlockCount := strings.Count(output, "DO $$")
+	if doBlockCount < 3 {
+		t.Errorf("Expected at least 3 DO blocks (one per column), got %d", doBlockCount)
+	}
+
+	// Verify IF NOT EXISTS logic
+	ifNotExistsCount := strings.Count(output, "IF NOT EXISTS")
+	if ifNotExistsCount < 3 {
+		t.Errorf("Expected at least 3 IF NOT EXISTS checks (one per column), got %d", ifNotExistsCount)
+	}
+}
+
+func TestWriteAddColumnStatements(t *testing.T) {
+	// Create a test database
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	// Create a table with a new column to be added
+	table := models.InitTable("products", "public")
+
+	idCol := models.InitColumn("id", "products", "public")
+	idCol.Type = "integer"
+	table.Columns["id"] = idCol
+
+	// New column with various properties
+	descCol := models.InitColumn("description", "products", "public")
+	descCol.Type = "text"
+	descCol.NotNull = false
+	table.Columns["description"] = descCol
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	// Create writer with output to buffer
+	var buf bytes.Buffer
+	options := &writers.WriterOptions{}
+	writer := NewWriter(options)
+	writer.writer = &buf
+
+	// Write ADD COLUMN statements
+	err := writer.WriteAddColumnStatements(db)
+	if err != nil {
+		t.Fatalf("WriteAddColumnStatements failed: %v", err)
+	}
+
+	output := buf.String()
+	t.Logf("Generated output:\n%s", output)
+
+	// Verify output contains expected elements
+	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN id integer") {
+		t.Errorf("Output missing ADD COLUMN for id\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN description text") {
+		t.Errorf("Output missing ADD COLUMN for description\nFull output:\n%s", output)
+	}
+	if !strings.Contains(output, "DO $$") {
+		t.Errorf("Output missing DO block\nFull output:\n%s", output)
+	}
+}

pkg/writers/sqlexec/writer.go

@@ -23,6 +23,11 @@ func NewWriter(options *writers.WriterOptions) *Writer {
 	}
 }
 
+// Options returns the writer options (useful for reading execution results)
+func (w *Writer) Options() *writers.WriterOptions {
+	return w.options
+}
+
 // WriteDatabase executes all scripts from all schemas in the database
 func (w *Writer) WriteDatabase(db *models.Database) error {
 	if db == nil {
@@ -92,6 +97,22 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 		return nil
 	}
 
+	// Check if we should ignore errors
+	ignoreErrors := false
+	if val, ok := w.options.Metadata["ignore_errors"].(bool); ok {
+		ignoreErrors = val
+	}
+
+	// Track failed scripts and execution counts
+	var failedScripts []struct {
+		name     string
+		priority int
+		sequence uint
+		err      error
+	}
+	successCount := 0
+	totalCount := 0
+
 	// Sort scripts by Priority (ascending), Sequence (ascending), then Name (ascending)
 	sortedScripts := make([]*models.Script, len(scripts))
 	copy(sortedScripts, scripts)
@@ -111,18 +132,49 @@ func (w *Writer) executeScripts(ctx context.Context, conn *pgx.Conn, scripts []*
 			continue
 		}
 
+		totalCount++
 		fmt.Printf("Executing script: %s (Priority=%d, Sequence=%d)\n",
 			script.Name, script.Priority, script.Sequence)
 
 		// Execute the SQL script
 		_, err := conn.Exec(ctx, script.SQL)
 		if err != nil {
-			return fmt.Errorf("failed to execute script %s (Priority=%d, Sequence=%d): %w",
+			if ignoreErrors {
+				fmt.Printf("⚠ Error executing %s: %v (continuing due to --ignore-errors)\n", script.Name, err)
+				failedScripts = append(failedScripts, struct {
+					name     string
+					priority int
+					sequence uint
+					err      error
+				}{
+					name:     script.Name,
+					priority: script.Priority,
+					sequence: script.Sequence,
+					err:      err,
+				})
+				continue
+			}
+			return fmt.Errorf("script %s (Priority=%d, Sequence=%d): %w",
 				script.Name, script.Priority, script.Sequence, err)
 		}
 
+		successCount++
 		fmt.Printf("✓ Successfully executed: %s\n", script.Name)
 	}
 
+	// Store execution results in metadata for caller
+	w.options.Metadata["execution_total"] = totalCount
+	w.options.Metadata["execution_success"] = successCount
+	w.options.Metadata["execution_failed"] = len(failedScripts)
+
+	// Print summary of failed scripts if any
+	if len(failedScripts) > 0 {
+		fmt.Printf("\n⚠ Failed Scripts Summary (%d failed):\n", len(failedScripts))
+		for i, failed := range failedScripts {
+			fmt.Printf("  %d. %s (Priority=%d, Sequence=%d)\n     Error: %v\n",
+				i+1, failed.name, failed.priority, failed.sequence, failed.err)
+		}
+	}
+
 	return nil
 }

pkg/writers/sqlite/README.md

@@ -0,0 +1,215 @@
+# SQLite Writer
+
+SQLite DDL (Data Definition Language) writer for RelSpec. Converts database schemas to SQLite-compatible SQL statements.
+
+## Features
+
+- **Automatic Schema Flattening** - SQLite doesn't support PostgreSQL-style schemas, so table names are automatically flattened (e.g., `public.users` → `public_users`)
+- **Type Mapping** - Converts PostgreSQL data types to SQLite type affinities (TEXT, INTEGER, REAL, NUMERIC, BLOB)
+- **Auto-Increment Detection** - Automatically converts SERIAL types and auto-increment columns to `INTEGER PRIMARY KEY AUTOINCREMENT`
+- **Function Translation** - Converts PostgreSQL functions to SQLite equivalents (e.g., `now()` → `CURRENT_TIMESTAMP`)
+- **Boolean Handling** - Maps boolean values to INTEGER (true=1, false=0)
+- **Constraint Generation** - Creates indexes, unique constraints, and documents foreign keys
+- **Identifier Quoting** - Properly quotes identifiers using double quotes
+
+## Usage
+
+### Convert PostgreSQL to SQLite
+
+```bash
+relspec convert --from pgsql --from-conn "postgres://user:pass@localhost/mydb" \
+                --to sqlite --to-path schema.sql
+```
+
+### Convert DBML to SQLite
+
+```bash
+relspec convert --from dbml --from-path schema.dbml \
+                --to sqlite --to-path schema.sql
+```
+
+### Multi-Schema Databases
+
+SQLite doesn't support schemas, so multi-schema databases are automatically flattened:
+
+```bash
+# Input has auth.users and public.posts
+# Output will have auth_users and public_posts
+relspec convert --from json --from-path multi_schema.json \
+                --to sqlite --to-path flattened.sql
+```
+
+## Type Mapping
+
+| PostgreSQL Type | SQLite Affinity | Examples |
+|----------------|-----------------|----------|
+| TEXT | TEXT | varchar, text, char, citext, uuid, timestamp, json |
+| INTEGER | INTEGER | int, integer, smallint, bigint, serial, boolean |
+| REAL | REAL | real, float, double precision |
+| NUMERIC | NUMERIC | numeric, decimal |
+| BLOB | BLOB | bytea, blob |
+
+## Auto-Increment Handling
+
+Columns are converted to `INTEGER PRIMARY KEY AUTOINCREMENT` when they meet these criteria:
+- Marked as primary key
+- Integer type
+- Have `AutoIncrement` flag set, OR
+- Type contains "serial", OR
+- Default value contains "nextval"
+
+**Example:**
+
+```sql
+-- Input (PostgreSQL)
+CREATE TABLE users (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(100)
+);
+
+-- Output (SQLite)
+CREATE TABLE "users" (
+    "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+    "name" TEXT
+);
+```
+
+## Default Value Translation
+
+| PostgreSQL | SQLite | Notes |
+|-----------|--------|-------|
+| `now()`, `CURRENT_TIMESTAMP` | `CURRENT_TIMESTAMP` | Timestamp functions |
+| `CURRENT_DATE` | `CURRENT_DATE` | Date function |
+| `CURRENT_TIME` | `CURRENT_TIME` | Time function |
+| `true`, `false` | `1`, `0` | Boolean values |
+| `gen_random_uuid()` | *(removed)* | SQLite has no built-in UUID |
+| `nextval(...)` | *(removed)* | Handled by AUTOINCREMENT |
+
+## Foreign Keys
+
+Foreign keys are generated as commented-out ALTER TABLE statements for reference:
+
+```sql
+-- Foreign key: fk_posts_user_id
+-- ALTER TABLE "posts" ADD CONSTRAINT "posts_fk_posts_user_id"
+--   FOREIGN KEY ("user_id")
+--   REFERENCES "users" ("id");
+-- Note: Foreign keys should be defined in CREATE TABLE for better SQLite compatibility
+```
+
+For production use, define foreign keys directly in the CREATE TABLE statement or execute the ALTER TABLE commands after creating all tables.
+
+## Constraints
+
+- **Primary Keys**: Inline for auto-increment columns, separate constraint for composite keys
+- **Unique Constraints**: Converted to `CREATE UNIQUE INDEX` statements
+- **Check Constraints**: Generated as comments (should be added to CREATE TABLE manually)
+- **Indexes**: Generated without PostgreSQL-specific features (no GIN, GiST, operator classes)
+
+## Output Structure
+
+Generated SQL follows this order:
+
+1. Header comments
+2. `PRAGMA foreign_keys = ON;`
+3. CREATE TABLE statements (sorted by schema, then table)
+4. CREATE INDEX statements
+5. CREATE UNIQUE INDEX statements (for unique constraints)
+6. Check constraint comments
+7. Foreign key comments
+
+## Example
+
+**Input (multi-schema PostgreSQL):**
+
+```sql
+CREATE SCHEMA auth;
+CREATE TABLE auth.users (
+    id SERIAL PRIMARY KEY,
+    username VARCHAR(50) UNIQUE NOT NULL,
+    created_at TIMESTAMP DEFAULT now()
+);
+
+CREATE SCHEMA public;
+CREATE TABLE public.posts (
+    id SERIAL PRIMARY KEY,
+    user_id INTEGER REFERENCES auth.users(id),
+    title VARCHAR(200) NOT NULL,
+    published BOOLEAN DEFAULT false
+);
+```
+
+**Output (SQLite with flattened schemas):**
+
+```sql
+-- SQLite Database Schema
+-- Database: mydb
+-- Generated by RelSpec
+-- Note: Schema names have been flattened (e.g., public.users -> public_users)
+
+-- Enable foreign key constraints
+PRAGMA foreign_keys = ON;
+
+-- Schema: auth (flattened into table names)
+
+CREATE TABLE "auth_users" (
+    "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+    "username" TEXT NOT NULL,
+    "created_at" TEXT DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE UNIQUE INDEX "auth_users_users_username_key" ON "auth_users" ("username");
+
+-- Schema: public (flattened into table names)
+
+CREATE TABLE "public_posts" (
+    "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+    "user_id" INTEGER NOT NULL,
+    "title" TEXT NOT NULL,
+    "published" INTEGER DEFAULT 0
+);
+
+-- Foreign key: posts_user_id_fkey
+-- ALTER TABLE "public_posts" ADD CONSTRAINT "public_posts_posts_user_id_fkey"
+--   FOREIGN KEY ("user_id")
+--   REFERENCES "auth_users" ("id");
+-- Note: Foreign keys should be defined in CREATE TABLE for better SQLite compatibility
+```
+
+## Programmatic Usage
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/sqlite"
+)
+
+func main() {
+    // Create writer (automatically enables schema flattening)
+    writer := sqlite.NewWriter(&writers.WriterOptions{
+        OutputPath: "schema.sql",
+    })
+
+    // Write database schema
+    db := &models.Database{
+        Name: "mydb",
+        Schemas: []*models.Schema{
+            // ... your schema data
+        },
+    }
+
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+## Notes
+
+- Schema flattening is **always enabled** for SQLite output (cannot be disabled)
+- Constraint and index names are prefixed with the flattened table name to avoid collisions
+- Generated SQL is compatible with SQLite 3.x
+- Foreign key constraints require `PRAGMA foreign_keys = ON;` to be enforced
+- For complex schemas, review and test the generated SQL before use in production

pkg/writers/sqlite/datatypes.go

@@ -0,0 +1,89 @@
+package sqlite
+
+import (
+	"strings"
+)
+
+// SQLite type affinities
+const (
+	TypeText    = "TEXT"
+	TypeInteger = "INTEGER"
+	TypeReal    = "REAL"
+	TypeNumeric = "NUMERIC"
+	TypeBlob    = "BLOB"
+)
+
+// MapPostgreSQLType maps PostgreSQL data types to SQLite type affinities
+func MapPostgreSQLType(pgType string) string {
+	// Normalize the type
+	normalized := strings.ToLower(strings.TrimSpace(pgType))
+
+	// Remove array notation if present
+	normalized = strings.TrimSuffix(normalized, "[]")
+
+	// Remove precision/scale if present
+	if idx := strings.Index(normalized, "("); idx != -1 {
+		normalized = normalized[:idx]
+	}
+
+	// Map to SQLite type affinity
+	switch normalized {
+	// TEXT affinity
+	case "varchar", "character varying", "text", "char", "character",
+		"citext", "uuid", "timestamp", "timestamptz", "timestamp with time zone",
+		"timestamp without time zone", "date", "time", "timetz", "time with time zone",
+		"time without time zone", "json", "jsonb", "xml", "inet", "cidr", "macaddr":
+		return TypeText
+
+	// INTEGER affinity
+	case "int", "int2", "int4", "int8", "integer", "smallint", "bigint",
+		"serial", "smallserial", "bigserial", "boolean", "bool":
+		return TypeInteger
+
+	// REAL affinity
+	case "real", "float", "float4", "float8", "double precision":
+		return TypeReal
+
+	// NUMERIC affinity
+	case "numeric", "decimal", "money":
+		return TypeNumeric
+
+	// BLOB affinity
+	case "bytea", "blob":
+		return TypeBlob
+
+	default:
+		// Default to TEXT for unknown types
+		return TypeText
+	}
+}
+
+// IsIntegerType checks if a column type should be treated as integer
+func IsIntegerType(colType string) bool {
+	normalized := strings.ToLower(strings.TrimSpace(colType))
+	normalized = strings.TrimSuffix(normalized, "[]")
+	if idx := strings.Index(normalized, "("); idx != -1 {
+		normalized = normalized[:idx]
+	}
+
+	switch normalized {
+	case "int", "int2", "int4", "int8", "integer", "smallint", "bigint",
+		"serial", "smallserial", "bigserial":
+		return true
+	default:
+		return false
+	}
+}
+
+// MapBooleanValue converts PostgreSQL boolean literals to SQLite (0/1)
+func MapBooleanValue(value string) string {
+	normalized := strings.ToLower(strings.TrimSpace(value))
+	switch normalized {
+	case "true", "t", "yes", "y", "1":
+		return "1"
+	case "false", "f", "no", "n", "0":
+		return "0"
+	default:
+		return value
+	}
+}

pkg/writers/sqlite/template_functions.go

@@ -0,0 +1,146 @@
+package sqlite
+
+import (
+	"fmt"
+	"strings"
+	"text/template"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+// GetTemplateFuncs returns template functions for SQLite SQL generation
+func GetTemplateFuncs(opts *writers.WriterOptions) template.FuncMap {
+	return template.FuncMap{
+		"quote_ident":      QuoteIdentifier,
+		"map_type":         MapPostgreSQLType,
+		"is_autoincrement": IsAutoIncrementCandidate,
+		"qualified_table_name": func(schema, table string) string {
+			return writers.QualifiedTableName(schema, table, opts.FlattenSchema)
+		},
+		"format_default": FormatDefault,
+		"format_constraint_name": func(schema, table, constraint string) string {
+			return FormatConstraintName(schema, table, constraint, opts)
+		},
+		"join":  strings.Join,
+		"lower": strings.ToLower,
+		"upper": strings.ToUpper,
+	}
+}
+
+// QuoteIdentifier quotes an identifier for SQLite (double quotes)
+func QuoteIdentifier(name string) string {
+	// SQLite uses double quotes for identifiers
+	// Escape any existing double quotes by doubling them
+	escaped := strings.ReplaceAll(name, `"`, `""`)
+	return fmt.Sprintf(`"%s"`, escaped)
+}
+
+// IsAutoIncrementCandidate checks if a column should use AUTOINCREMENT
+func IsAutoIncrementCandidate(col *models.Column) bool {
+	// Must be a primary key
+	if !col.IsPrimaryKey {
+		return false
+	}
+
+	// Must be an integer type
+	if !IsIntegerType(col.Type) {
+		return false
+	}
+
+	// Check AutoIncrement field
+	if col.AutoIncrement {
+		return true
+	}
+
+	// Check if default suggests auto-increment
+	if col.Default != nil {
+		defaultStr, ok := col.Default.(string)
+		if ok {
+			defaultLower := strings.ToLower(defaultStr)
+			if strings.Contains(defaultLower, "nextval") ||
+				strings.Contains(defaultLower, "autoincrement") ||
+				strings.Contains(defaultLower, "auto_increment") {
+				return true
+			}
+		}
+	}
+
+	// Serial types are auto-increment
+	typeLower := strings.ToLower(col.Type)
+	return strings.Contains(typeLower, "serial")
+}
+
+// FormatDefault formats a default value for SQLite
+func FormatDefault(col *models.Column) string {
+	if col.Default == nil {
+		return ""
+	}
+
+	// Skip auto-increment defaults (handled by AUTOINCREMENT keyword)
+	if IsAutoIncrementCandidate(col) {
+		return ""
+	}
+
+	// Convert to string
+	defaultStr, ok := col.Default.(string)
+	if !ok {
+		// If not a string, convert to string representation
+		defaultStr = fmt.Sprintf("%v", col.Default)
+	}
+
+	if defaultStr == "" {
+		return ""
+	}
+
+	// Convert PostgreSQL-specific functions to SQLite equivalents
+	defaultLower := strings.ToLower(defaultStr)
+
+	// Current timestamp functions
+	if strings.Contains(defaultLower, "current_timestamp") ||
+		strings.Contains(defaultLower, "now()") {
+		return "CURRENT_TIMESTAMP"
+	}
+
+	// Current date
+	if strings.Contains(defaultLower, "current_date") {
+		return "CURRENT_DATE"
+	}
+
+	// Current time
+	if strings.Contains(defaultLower, "current_time") {
+		return "CURRENT_TIME"
+	}
+
+	// Boolean values
+	sqliteType := MapPostgreSQLType(col.Type)
+	if sqliteType == TypeInteger {
+		typeLower := strings.ToLower(col.Type)
+		if strings.Contains(typeLower, "bool") {
+			return MapBooleanValue(defaultStr)
+		}
+	}
+
+	// UUID generation - SQLite doesn't have built-in UUID, comment it out
+	if strings.Contains(defaultLower, "uuid") || strings.Contains(defaultLower, "gen_random_uuid") {
+		return "" // Remove UUID defaults, users must handle this
+	}
+
+	// Remove PostgreSQL-specific casting
+	defaultStr = strings.ReplaceAll(defaultStr, "::text", "")
+	defaultStr = strings.ReplaceAll(defaultStr, "::integer", "")
+	defaultStr = strings.ReplaceAll(defaultStr, "::bigint", "")
+	defaultStr = strings.ReplaceAll(defaultStr, "::boolean", "")
+
+	return defaultStr
+}
+
+// FormatConstraintName formats a constraint name with table prefix if flattening
+func FormatConstraintName(schema, table, constraint string, opts *writers.WriterOptions) string {
+	if opts.FlattenSchema && schema != "" {
+		// Prefix constraint with flattened table name
+		flatTable := writers.QualifiedTableName(schema, table, opts.FlattenSchema)
+		return fmt.Sprintf("%s_%s", flatTable, constraint)
+	}
+	return constraint
+}

pkg/writers/sqlite/templates.go

@@ -0,0 +1,174 @@
+package sqlite
+
+import (
+	"bytes"
+	"embed"
+	"fmt"
+	"text/template"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+//go:embed templates/*.tmpl
+var templateFS embed.FS
+
+// TemplateExecutor manages and executes SQLite SQL templates
+type TemplateExecutor struct {
+	templates *template.Template
+	options   *writers.WriterOptions
+}
+
+// NewTemplateExecutor creates a new template executor for SQLite
+func NewTemplateExecutor(opts *writers.WriterOptions) (*TemplateExecutor, error) {
+	// Create template with SQLite-specific functions
+	funcMap := GetTemplateFuncs(opts)
+
+	tmpl, err := template.New("").Funcs(funcMap).ParseFS(templateFS, "templates/*.tmpl")
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse templates: %w", err)
+	}
+
+	return &TemplateExecutor{
+		templates: tmpl,
+		options:   opts,
+	}, nil
+}
+
+// Template data structures
+
+// TableTemplateData contains data for table template
+type TableTemplateData struct {
+	Schema     string
+	Name       string
+	Columns    []*models.Column
+	PrimaryKey *models.Constraint
+}
+
+// IndexTemplateData contains data for index template
+type IndexTemplateData struct {
+	Schema  string
+	Table   string
+	Name    string
+	Columns []string
+}
+
+// ConstraintTemplateData contains data for constraint templates
+type ConstraintTemplateData struct {
+	Schema         string
+	Table          string
+	Name           string
+	Columns        []string
+	Expression     string
+	ForeignSchema  string
+	ForeignTable   string
+	ForeignColumns []string
+	OnDelete       string
+	OnUpdate       string
+}
+
+// Execute methods
+
+// ExecutePragmaForeignKeys executes the pragma foreign keys template
+func (te *TemplateExecutor) ExecutePragmaForeignKeys() (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "pragma_foreign_keys.tmpl", nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute pragma_foreign_keys template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateTable executes the create table template
+func (te *TemplateExecutor) ExecuteCreateTable(data TableTemplateData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_table.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_table template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateIndex executes the create index template
+func (te *TemplateExecutor) ExecuteCreateIndex(data IndexTemplateData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_index.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_index template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateUniqueConstraint executes the create unique constraint template
+func (te *TemplateExecutor) ExecuteCreateUniqueConstraint(data ConstraintTemplateData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_unique_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_unique_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateCheckConstraint executes the create check constraint template
+func (te *TemplateExecutor) ExecuteCreateCheckConstraint(data ConstraintTemplateData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_check_constraint.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_check_constraint template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// ExecuteCreateForeignKey executes the create foreign key template
+func (te *TemplateExecutor) ExecuteCreateForeignKey(data ConstraintTemplateData) (string, error) {
+	var buf bytes.Buffer
+	err := te.templates.ExecuteTemplate(&buf, "create_foreign_key.tmpl", data)
+	if err != nil {
+		return "", fmt.Errorf("failed to execute create_foreign_key template: %w", err)
+	}
+	return buf.String(), nil
+}
+
+// Helper functions to build template data from models
+
+// BuildTableTemplateData builds TableTemplateData from a models.Table
+func BuildTableTemplateData(schema string, table *models.Table) TableTemplateData {
+	// Get sorted columns
+	columns := make([]*models.Column, 0, len(table.Columns))
+	for _, col := range table.Columns {
+		columns = append(columns, col)
+	}
+
+	// Find primary key constraint
+	var pk *models.Constraint
+	for _, constraint := range table.Constraints {
+		if constraint.Type == models.PrimaryKeyConstraint {
+			pk = constraint
+			break
+		}
+	}
+
+	// If no explicit primary key constraint, build one from columns with IsPrimaryKey=true
+	if pk == nil {
+		pkCols := []string{}
+		for _, col := range table.Columns {
+			if col.IsPrimaryKey {
+				pkCols = append(pkCols, col.Name)
+			}
+		}
+		if len(pkCols) > 0 {
+			pk = &models.Constraint{
+				Name:    "pk_" + table.Name,
+				Type:    models.PrimaryKeyConstraint,
+				Columns: pkCols,
+			}
+		}
+	}
+
+	return TableTemplateData{
+		Schema:     schema,
+		Name:       table.Name,
+		Columns:    columns,
+		PrimaryKey: pk,
+	}
+}

pkg/writers/sqlite/templates/create_check_constraint.tmpl

@@ -0,0 +1,4 @@
+-- Check constraint: {{.Name}}
+-- {{.Expression}}
+-- Note: SQLite supports CHECK constraints in CREATE TABLE or ALTER TABLE ADD CHECK
+-- This must be added manually to the table definition above

pkg/writers/sqlite/templates/create_foreign_key.tmpl

@@ -0,0 +1,6 @@
+-- Foreign key: {{.Name}}
+-- ALTER TABLE {{quote_ident (qualified_table_name .Schema .Table)}} ADD CONSTRAINT {{quote_ident (format_constraint_name .Schema .Table .Name)}}
+--   FOREIGN KEY ({{range $i, $col := .Columns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}})
+--   REFERENCES {{quote_ident (qualified_table_name .ForeignSchema .ForeignTable)}} ({{range $i, $col := .ForeignColumns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}})
+--   {{if .OnDelete}}ON DELETE {{.OnDelete}}{{end}}{{if .OnUpdate}} ON UPDATE {{.OnUpdate}}{{end}};
+-- Note: Foreign keys should be defined in CREATE TABLE for better SQLite compatibility

pkg/writers/sqlite/templates/create_index.tmpl

@@ -0,0 +1 @@
+CREATE INDEX {{quote_ident (format_constraint_name .Schema .Table .Name)}} ON {{quote_ident (qualified_table_name .Schema .Table)}} ({{range $i, $col := .Columns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}});

pkg/writers/sqlite/templates/create_table.tmpl

@@ -0,0 +1,9 @@
+CREATE TABLE {{quote_ident (qualified_table_name .Schema .Name)}} (
+{{- $hasAutoIncrement := false}}
+{{- range $i, $col := .Columns}}{{if $i}},{{end}}
+    {{quote_ident $col.Name}} {{map_type $col.Type}}{{if is_autoincrement $col}}{{$hasAutoIncrement = true}} PRIMARY KEY AUTOINCREMENT{{else}}{{if $col.NotNull}} NOT NULL{{end}}{{if ne (format_default $col) ""}} DEFAULT {{format_default $col}}{{end}}{{end}}
+{{- end}}
+{{- if and .PrimaryKey (not $hasAutoIncrement)}}{{if gt (len .Columns) 0}},{{end}}
+    PRIMARY KEY ({{range $i, $colName := .PrimaryKey.Columns}}{{if $i}}, {{end}}{{quote_ident $colName}}{{end}})
+{{- end}}
+);

pkg/writers/sqlite/templates/create_unique_constraint.tmpl

@@ -0,0 +1 @@
+CREATE UNIQUE INDEX {{quote_ident (format_constraint_name .Schema .Table .Name)}} ON {{quote_ident (qualified_table_name .Schema .Table)}} ({{range $i, $col := .Columns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}});

pkg/writers/sqlite/templates/pragma_foreign_keys.tmpl

@@ -0,0 +1,2 @@
+-- Enable foreign key constraints
+PRAGMA foreign_keys = ON;

pkg/writers/sqlite/writer.go

@@ -0,0 +1,291 @@
+package sqlite
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+// Writer implements the Writer interface for SQLite SQL output
+type Writer struct {
+	options  *writers.WriterOptions
+	writer   io.Writer
+	executor *TemplateExecutor
+}
+
+// NewWriter creates a new SQLite SQL writer
+// SQLite doesn't support schemas, so FlattenSchema is automatically enabled
+func NewWriter(options *writers.WriterOptions) *Writer {
+	// Force schema flattening for SQLite
+	options.FlattenSchema = true
+
+	executor, _ := NewTemplateExecutor(options)
+	return &Writer{
+		options:  options,
+		executor: executor,
+	}
+}
+
+// WriteDatabase writes the entire database schema as SQLite SQL
+func (w *Writer) WriteDatabase(db *models.Database) error {
+	var writer io.Writer
+	var file *os.File
+	var err error
+
+	// Use existing writer if already set (for testing)
+	if w.writer != nil {
+		writer = w.writer
+	} else if w.options.OutputPath != "" {
+		// Determine output destination
+		file, err = os.Create(w.options.OutputPath)
+		if err != nil {
+			return fmt.Errorf("failed to create output file: %w", err)
+		}
+		defer file.Close()
+		writer = file
+	} else {
+		writer = os.Stdout
+	}
+
+	w.writer = writer
+
+	// Write header comment
+	fmt.Fprintf(w.writer, "-- SQLite Database Schema\n")
+	fmt.Fprintf(w.writer, "-- Database: %s\n", db.Name)
+	fmt.Fprintf(w.writer, "-- Generated by RelSpec\n")
+	fmt.Fprintf(w.writer, "-- Note: Schema names have been flattened (e.g., public.users -> public_users)\n\n")
+
+	// Enable foreign keys
+	pragma, err := w.executor.ExecutePragmaForeignKeys()
+	if err != nil {
+		return fmt.Errorf("failed to generate pragma statement: %w", err)
+	}
+	fmt.Fprintf(w.writer, "%s\n", pragma)
+
+	// Process each schema in the database
+	for _, schema := range db.Schemas {
+		if err := w.WriteSchema(schema); err != nil {
+			return fmt.Errorf("failed to write schema %s: %w", schema.Name, err)
+		}
+	}
+
+	return nil
+}
+
+// WriteSchema writes a single schema as SQLite SQL
+func (w *Writer) WriteSchema(schema *models.Schema) error {
+	// SQLite doesn't have schemas, so we just write a comment
+	if schema.Name != "" {
+		fmt.Fprintf(w.writer, "-- Schema: %s (flattened into table names)\n\n", schema.Name)
+	}
+
+	// Phase 1: Create tables
+	for _, table := range schema.Tables {
+		if err := w.writeTable(schema.Name, table); err != nil {
+			return fmt.Errorf("failed to write table %s: %w", table.Name, err)
+		}
+	}
+
+	// Phase 2: Create indexes
+	for _, table := range schema.Tables {
+		if err := w.writeIndexes(schema.Name, table); err != nil {
+			return fmt.Errorf("failed to write indexes for table %s: %w", table.Name, err)
+		}
+	}
+
+	// Phase 3: Create unique constraints (as unique indexes)
+	for _, table := range schema.Tables {
+		if err := w.writeUniqueConstraints(schema.Name, table); err != nil {
+			return fmt.Errorf("failed to write unique constraints for table %s: %w", table.Name, err)
+		}
+	}
+
+	// Phase 4: Check constraints (as comments, since SQLite requires them in CREATE TABLE)
+	for _, table := range schema.Tables {
+		if err := w.writeCheckConstraints(schema.Name, table); err != nil {
+			return fmt.Errorf("failed to write check constraints for table %s: %w", table.Name, err)
+		}
+	}
+
+	// Phase 5: Foreign keys (as comments for compatibility)
+	for _, table := range schema.Tables {
+		if err := w.writeForeignKeys(schema.Name, table); err != nil {
+			return fmt.Errorf("failed to write foreign keys for table %s: %w", table.Name, err)
+		}
+	}
+
+	return nil
+}
+
+// WriteTable writes a single table as SQLite SQL
+func (w *Writer) WriteTable(table *models.Table) error {
+	return w.writeTable("", table)
+}
+
+// writeTable is the internal implementation
+func (w *Writer) writeTable(schema string, table *models.Table) error {
+	// Build table template data
+	data := BuildTableTemplateData(schema, table)
+
+	// Execute template
+	sql, err := w.executor.ExecuteCreateTable(data)
+	if err != nil {
+		return fmt.Errorf("failed to execute create table template: %w", err)
+	}
+
+	fmt.Fprintf(w.writer, "%s\n", sql)
+	return nil
+}
+
+// writeIndexes writes indexes for a table
+func (w *Writer) writeIndexes(schema string, table *models.Table) error {
+	for _, index := range table.Indexes {
+		// Skip primary key indexes
+		if strings.HasSuffix(index.Name, "_pkey") {
+			continue
+		}
+
+		// Skip unique indexes (handled separately as unique constraints)
+		if index.Unique {
+			continue
+		}
+
+		data := IndexTemplateData{
+			Schema:  schema,
+			Table:   table.Name,
+			Name:    index.Name,
+			Columns: index.Columns,
+		}
+
+		sql, err := w.executor.ExecuteCreateIndex(data)
+		if err != nil {
+			return fmt.Errorf("failed to execute create index template: %w", err)
+		}
+
+		fmt.Fprintf(w.writer, "%s\n", sql)
+	}
+
+	return nil
+}
+
+// writeUniqueConstraints writes unique constraints as unique indexes
+func (w *Writer) writeUniqueConstraints(schema string, table *models.Table) error {
+	for _, constraint := range table.Constraints {
+		if constraint.Type != models.UniqueConstraint {
+			continue
+		}
+
+		data := ConstraintTemplateData{
+			Schema:  schema,
+			Table:   table.Name,
+			Name:    constraint.Name,
+			Columns: constraint.Columns,
+		}
+
+		sql, err := w.executor.ExecuteCreateUniqueConstraint(data)
+		if err != nil {
+			return fmt.Errorf("failed to execute create unique constraint template: %w", err)
+		}
+
+		fmt.Fprintf(w.writer, "%s\n", sql)
+	}
+
+	// Also handle unique indexes from the Indexes map
+	for _, index := range table.Indexes {
+		if !index.Unique {
+			continue
+		}
+
+		// Skip if already handled as a constraint
+		alreadyHandled := false
+		for _, constraint := range table.Constraints {
+			if constraint.Type == models.UniqueConstraint && constraint.Name == index.Name {
+				alreadyHandled = true
+				break
+			}
+		}
+		if alreadyHandled {
+			continue
+		}
+
+		data := ConstraintTemplateData{
+			Schema:  schema,
+			Table:   table.Name,
+			Name:    index.Name,
+			Columns: index.Columns,
+		}
+
+		sql, err := w.executor.ExecuteCreateUniqueConstraint(data)
+		if err != nil {
+			return fmt.Errorf("failed to execute create unique index template: %w", err)
+		}
+
+		fmt.Fprintf(w.writer, "%s\n", sql)
+	}
+
+	return nil
+}
+
+// writeCheckConstraints writes check constraints as comments
+func (w *Writer) writeCheckConstraints(schema string, table *models.Table) error {
+	for _, constraint := range table.Constraints {
+		if constraint.Type != models.CheckConstraint {
+			continue
+		}
+
+		data := ConstraintTemplateData{
+			Schema:     schema,
+			Table:      table.Name,
+			Name:       constraint.Name,
+			Expression: constraint.Expression,
+		}
+
+		sql, err := w.executor.ExecuteCreateCheckConstraint(data)
+		if err != nil {
+			return fmt.Errorf("failed to execute create check constraint template: %w", err)
+		}
+
+		fmt.Fprintf(w.writer, "%s\n", sql)
+	}
+
+	return nil
+}
+
+// writeForeignKeys writes foreign keys as comments
+func (w *Writer) writeForeignKeys(schema string, table *models.Table) error {
+	for _, constraint := range table.Constraints {
+		if constraint.Type != models.ForeignKeyConstraint {
+			continue
+		}
+
+		refSchema := constraint.ReferencedSchema
+		if refSchema == "" {
+			refSchema = schema
+		}
+
+		data := ConstraintTemplateData{
+			Schema:         schema,
+			Table:          table.Name,
+			Name:           constraint.Name,
+			Columns:        constraint.Columns,
+			ForeignSchema:  refSchema,
+			ForeignTable:   constraint.ReferencedTable,
+			ForeignColumns: constraint.ReferencedColumns,
+			OnDelete:       constraint.OnDelete,
+			OnUpdate:       constraint.OnUpdate,
+		}
+
+		sql, err := w.executor.ExecuteCreateForeignKey(data)
+		if err != nil {
+			return fmt.Errorf("failed to execute create foreign key template: %w", err)
+		}
+
+		fmt.Fprintf(w.writer, "%s\n", sql)
+	}
+
+	return nil
+}

pkg/writers/sqlite/writer_test.go

@@ -0,0 +1,418 @@
+package sqlite
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+func TestNewWriter(t *testing.T) {
+	opts := &writers.WriterOptions{
+		OutputPath:     "/tmp/test.sql",
+		FlattenSchema:  false, // Should be forced to true
+	}
+
+	writer := NewWriter(opts)
+
+	if !writer.options.FlattenSchema {
+		t.Error("Expected FlattenSchema to be forced to true for SQLite")
+	}
+}
+
+func TestWriteDatabase(t *testing.T) {
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "users",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "serial",
+								NotNull:      true,
+								IsPrimaryKey: true,
+								Default:      "nextval('users_id_seq'::regclass)",
+							},
+							"email": {
+								Name:    "email",
+								Type:    "varchar(255)",
+								NotNull: true,
+							},
+							"active": {
+								Name:    "active",
+								Type:    "boolean",
+								NotNull: true,
+								Default: "true",
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"pk_users": {
+								Name:    "pk_users",
+								Type:    models.PrimaryKeyConstraint,
+								Columns: []string{"id"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	opts := &writers.WriterOptions{}
+	writer := NewWriter(opts)
+	writer.writer = &buf
+
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Check for expected elements
+	if !strings.Contains(output, "PRAGMA foreign_keys = ON") {
+		t.Error("Expected PRAGMA foreign_keys statement")
+	}
+
+	if !strings.Contains(output, "CREATE TABLE") {
+		t.Error("Expected CREATE TABLE statement")
+	}
+
+	if !strings.Contains(output, "\"public_users\"") {
+		t.Error("Expected flattened table name public_users")
+	}
+
+	if !strings.Contains(output, "INTEGER PRIMARY KEY AUTOINCREMENT") {
+		t.Error("Expected autoincrement for serial primary key")
+	}
+
+	if !strings.Contains(output, "TEXT") {
+		t.Error("Expected TEXT type for varchar")
+	}
+
+	// Boolean should be mapped to INTEGER with default 1
+	if !strings.Contains(output, "active") {
+		t.Error("Expected active column")
+	}
+}
+
+func TestDataTypeMapping(t *testing.T) {
+	tests := []struct {
+		pgType   string
+		expected string
+	}{
+		{"varchar(255)", "TEXT"},
+		{"text", "TEXT"},
+		{"integer", "INTEGER"},
+		{"bigint", "INTEGER"},
+		{"serial", "INTEGER"},
+		{"boolean", "INTEGER"},
+		{"real", "REAL"},
+		{"double precision", "REAL"},
+		{"numeric(10,2)", "NUMERIC"},
+		{"decimal", "NUMERIC"},
+		{"bytea", "BLOB"},
+		{"timestamp", "TEXT"},
+		{"uuid", "TEXT"},
+		{"json", "TEXT"},
+		{"jsonb", "TEXT"},
+	}
+
+	for _, tt := range tests {
+		result := MapPostgreSQLType(tt.pgType)
+		if result != tt.expected {
+			t.Errorf("MapPostgreSQLType(%q) = %q, want %q", tt.pgType, result, tt.expected)
+		}
+	}
+}
+
+func TestIsAutoIncrementCandidate(t *testing.T) {
+	tests := []struct {
+		name     string
+		col      *models.Column
+		expected bool
+	}{
+		{
+			name: "serial primary key",
+			col: &models.Column{
+				Name:         "id",
+				Type:         "serial",
+				IsPrimaryKey: true,
+				Default:      "nextval('seq')",
+			},
+			expected: true,
+		},
+		{
+			name: "integer primary key with nextval",
+			col: &models.Column{
+				Name:         "id",
+				Type:         "integer",
+				IsPrimaryKey: true,
+				Default:      "nextval('users_id_seq'::regclass)",
+			},
+			expected: true,
+		},
+		{
+			name: "integer not primary key",
+			col: &models.Column{
+				Name:         "count",
+				Type:         "integer",
+				IsPrimaryKey: false,
+				Default:      "0",
+			},
+			expected: false,
+		},
+		{
+			name: "varchar primary key",
+			col: &models.Column{
+				Name:         "code",
+				Type:         "varchar",
+				IsPrimaryKey: true,
+			},
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := IsAutoIncrementCandidate(tt.col)
+			if result != tt.expected {
+				t.Errorf("IsAutoIncrementCandidate() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestFormatDefault(t *testing.T) {
+	tests := []struct {
+		name     string
+		col      *models.Column
+		expected string
+	}{
+		{
+			name: "current_timestamp",
+			col: &models.Column{
+				Type:    "timestamp",
+				Default: "CURRENT_TIMESTAMP",
+			},
+			expected: "CURRENT_TIMESTAMP",
+		},
+		{
+			name: "now()",
+			col: &models.Column{
+				Type:    "timestamp",
+				Default: "now()",
+			},
+			expected: "CURRENT_TIMESTAMP",
+		},
+		{
+			name: "boolean true",
+			col: &models.Column{
+				Type:    "boolean",
+				Default: "true",
+			},
+			expected: "1",
+		},
+		{
+			name: "boolean false",
+			col: &models.Column{
+				Type:    "boolean",
+				Default: "false",
+			},
+			expected: "0",
+		},
+		{
+			name: "serial autoincrement",
+			col: &models.Column{
+				Type:         "serial",
+				IsPrimaryKey: true,
+				Default:      "nextval('seq')",
+			},
+			expected: "",
+		},
+		{
+			name: "uuid default removed",
+			col: &models.Column{
+				Type:    "uuid",
+				Default: "gen_random_uuid()",
+			},
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := FormatDefault(tt.col)
+			if result != tt.expected {
+				t.Errorf("FormatDefault() = %q, want %q", result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestWriteSchema_MultiSchema(t *testing.T) {
+	db := &models.Database{
+		Name: "testdb",
+		Schemas: []*models.Schema{
+			{
+				Name: "auth",
+				Tables: []*models.Table{
+					{
+						Name: "sessions",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "uuid",
+								NotNull:      true,
+								IsPrimaryKey: true,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"pk_sessions": {
+								Name:    "pk_sessions",
+								Type:    models.PrimaryKeyConstraint,
+								Columns: []string{"id"},
+							},
+						},
+					},
+				},
+			},
+			{
+				Name: "public",
+				Tables: []*models.Table{
+					{
+						Name: "posts",
+						Columns: map[string]*models.Column{
+							"id": {
+								Name:         "id",
+								Type:         "integer",
+								NotNull:      true,
+								IsPrimaryKey: true,
+							},
+						},
+						Constraints: map[string]*models.Constraint{
+							"pk_posts": {
+								Name:    "pk_posts",
+								Type:    models.PrimaryKeyConstraint,
+								Columns: []string{"id"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	opts := &writers.WriterOptions{}
+	writer := NewWriter(opts)
+	writer.writer = &buf
+
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Check for flattened table names from both schemas
+	if !strings.Contains(output, "\"auth_sessions\"") {
+		t.Error("Expected flattened table name auth_sessions")
+	}
+
+	if !strings.Contains(output, "\"public_posts\"") {
+		t.Error("Expected flattened table name public_posts")
+	}
+}
+
+func TestWriteIndexes(t *testing.T) {
+	table := &models.Table{
+		Name: "users",
+		Columns: map[string]*models.Column{
+			"email": {
+				Name: "email",
+				Type: "varchar(255)",
+			},
+		},
+		Indexes: map[string]*models.Index{
+			"idx_users_email": {
+				Name:    "idx_users_email",
+				Columns: []string{"email"},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	opts := &writers.WriterOptions{}
+	writer := NewWriter(opts)
+	writer.writer = &buf
+
+	err := writer.writeIndexes("public", table)
+	if err != nil {
+		t.Fatalf("writeIndexes failed: %v", err)
+	}
+
+	output := buf.String()
+
+	if !strings.Contains(output, "CREATE INDEX") {
+		t.Error("Expected CREATE INDEX statement")
+	}
+
+	if !strings.Contains(output, "public_users_idx_users_email") {
+		t.Errorf("Expected flattened index name public_users_idx_users_email, got output:\n%s", output)
+	}
+}
+
+func TestWriteUniqueConstraints(t *testing.T) {
+	table := &models.Table{
+		Name: "users",
+		Constraints: map[string]*models.Constraint{
+			"uk_users_email": {
+				Name:    "uk_users_email",
+				Type:    models.UniqueConstraint,
+				Columns: []string{"email"},
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+	opts := &writers.WriterOptions{}
+	writer := NewWriter(opts)
+	writer.writer = &buf
+
+	err := writer.writeUniqueConstraints("public", table)
+	if err != nil {
+		t.Fatalf("writeUniqueConstraints failed: %v", err)
+	}
+
+	output := buf.String()
+
+	if !strings.Contains(output, "CREATE UNIQUE INDEX") {
+		t.Error("Expected CREATE UNIQUE INDEX statement")
+	}
+}
+
+func TestQuoteIdentifier(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"users", `"users"`},
+		{"public_users", `"public_users"`},
+		{`user"name`, `"user""name"`}, // Double quotes should be escaped
+	}
+
+	for _, tt := range tests {
+		result := QuoteIdentifier(tt.input)
+		if result != tt.expected {
+			t.Errorf("QuoteIdentifier(%q) = %q, want %q", tt.input, result, tt.expected)
+		}
+	}
+}

pkg/writers/writer.go

@@ -28,10 +28,29 @@ type WriterOptions struct {
 	// PackageName is the Go package name (for code generation)
 	PackageName string
 
+	// FlattenSchema disables schema.table dot notation and instead joins
+	// schema and table with an underscore (e.g., "public_users").
+	// Useful for databases like SQLite that do not support schemas.
+	FlattenSchema bool
+
 	// Additional options can be added here as needed
 	Metadata map[string]interface{}
 }
 
+// QualifiedTableName returns a schema-qualified table name.
+// When flatten is true, schema and table are joined with underscore (e.g., "schema_table").
+// When flatten is false, they are dot-separated (e.g., "schema.table").
+// If schema is empty, just the table name is returned regardless of flatten.
+func QualifiedTableName(schema, table string, flatten bool) string {
+	if schema == "" {
+		return table
+	}
+	if flatten {
+		return schema + "_" + table
+	}
+	return schema + "." + table
+}
+
 // SanitizeFilename removes quotes, comments, and invalid characters from identifiers
 // to make them safe for use in filenames. This handles:
 // - Double and single quotes: "table_name" or 'table_name' -> table_name

vendor/github.com/dustin/go-humanize/.travis.yml

@@ -0,0 +1,21 @@
+sudo: false
+language: go
+go_import_path: github.com/dustin/go-humanize
+go:
+  - 1.13.x
+  - 1.14.x
+  - 1.15.x
+  - 1.16.x
+  - stable
+  - master
+matrix:
+  allow_failures:
+    - go: master
+  fast_finish: true
+install:
+  - # Do nothing. This is needed to prevent default install action "go get -t -v ./..." from happening here (we want it to happen inside script step).
+script:
+  - diff -u <(echo -n) <(gofmt -d -s .)
+  - go vet .
+  - go install -v -race ./...
+  - go test -v -race ./...

vendor/github.com/dustin/go-humanize/LICENSE

@@ -0,0 +1,21 @@
+Copyright (c) 2005-2008  Dustin Sallings <dustin@spy.net>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+<http://www.opensource.org/licenses/mit-license.php>

vendor/github.com/dustin/go-humanize/README.markdown

@@ -0,0 +1,124 @@
+# Humane Units [![Build Status](https://travis-ci.org/dustin/go-humanize.svg?branch=master)](https://travis-ci.org/dustin/go-humanize) [![GoDoc](https://godoc.org/github.com/dustin/go-humanize?status.svg)](https://godoc.org/github.com/dustin/go-humanize)
+
+Just a few functions for helping humanize times and sizes.
+
+`go get` it as `github.com/dustin/go-humanize`, import it as
+`"github.com/dustin/go-humanize"`, use it as `humanize`.
+
+See [godoc](https://pkg.go.dev/github.com/dustin/go-humanize) for
+complete documentation.
+
+## Sizes
+
+This lets you take numbers like `82854982` and convert them to useful
+strings like, `83 MB` or `79 MiB` (whichever you prefer).
+
+Example:
+
+```go
+fmt.Printf("That file is %s.", humanize.Bytes(82854982)) // That file is 83 MB.
+```
+
+## Times
+
+This lets you take a `time.Time` and spit it out in relative terms.
+For example, `12 seconds ago` or `3 days from now`.
+
+Example:
+
+```go
+fmt.Printf("This was touched %s.", humanize.Time(someTimeInstance)) // This was touched 7 hours ago.
+```
+
+Thanks to Kyle Lemons for the time implementation from an IRC
+conversation one day. It's pretty neat.
+
+## Ordinals
+
+From a [mailing list discussion][odisc] where a user wanted to be able
+to label ordinals.
+
+    0 -> 0th
+    1 -> 1st
+    2 -> 2nd
+    3 -> 3rd
+    4 -> 4th
+    [...]
+
+Example:
+
+```go
+fmt.Printf("You're my %s best friend.", humanize.Ordinal(193)) // You are my 193rd best friend.
+```
+
+## Commas
+
+Want to shove commas into numbers? Be my guest.
+
+    0 -> 0
+    100 -> 100
+    1000 -> 1,000
+    1000000000 -> 1,000,000,000
+    -100000 -> -100,000
+
+Example:
+
+```go
+fmt.Printf("You owe $%s.\n", humanize.Comma(6582491)) // You owe $6,582,491.
+```
+
+## Ftoa
+
+Nicer float64 formatter that removes trailing zeros.
+
+```go
+fmt.Printf("%f", 2.24)                // 2.240000
+fmt.Printf("%s", humanize.Ftoa(2.24)) // 2.24
+fmt.Printf("%f", 2.0)                 // 2.000000
+fmt.Printf("%s", humanize.Ftoa(2.0))  // 2
+```
+
+## SI notation
+
+Format numbers with [SI notation][sinotation].
+
+Example:
+
+```go
+humanize.SI(0.00000000223, "M") // 2.23 nM
+```
+
+## English-specific functions
+
+The following functions are in the `humanize/english` subpackage.
+
+### Plurals
+
+Simple English pluralization
+
+```go
+english.PluralWord(1, "object", "") // object
+english.PluralWord(42, "object", "") // objects
+english.PluralWord(2, "bus", "") // buses
+english.PluralWord(99, "locus", "loci") // loci
+
+english.Plural(1, "object", "") // 1 object
+english.Plural(42, "object", "") // 42 objects
+english.Plural(2, "bus", "") // 2 buses
+english.Plural(99, "locus", "loci") // 99 loci
+```
+
+### Word series
+
+Format comma-separated words lists with conjuctions:
+
+```go
+english.WordSeries([]string{"foo"}, "and") // foo
+english.WordSeries([]string{"foo", "bar"}, "and") // foo and bar
+english.WordSeries([]string{"foo", "bar", "baz"}, "and") // foo, bar and baz
+
+english.OxfordWordSeries([]string{"foo", "bar", "baz"}, "and") // foo, bar, and baz
+```
+
+[odisc]: https://groups.google.com/d/topic/golang-nuts/l8NhI74jl-4/discussion
+[sinotation]: http://en.wikipedia.org/wiki/Metric_prefix

vendor/github.com/dustin/go-humanize/big.go

@@ -0,0 +1,31 @@
+package humanize
+
+import (
+	"math/big"
+)
+
+// order of magnitude (to a max order)
+func oomm(n, b *big.Int, maxmag int) (float64, int) {
+	mag := 0
+	m := &big.Int{}
+	for n.Cmp(b) >= 0 {
+		n.DivMod(n, b, m)
+		mag++
+		if mag == maxmag && maxmag >= 0 {
+			break
+		}
+	}
+	return float64(n.Int64()) + (float64(m.Int64()) / float64(b.Int64())), mag
+}
+
+// total order of magnitude
+// (same as above, but with no upper limit)
+func oom(n, b *big.Int) (float64, int) {
+	mag := 0
+	m := &big.Int{}
+	for n.Cmp(b) >= 0 {
+		n.DivMod(n, b, m)
+		mag++
+	}
+	return float64(n.Int64()) + (float64(m.Int64()) / float64(b.Int64())), mag
+}

vendor/github.com/dustin/go-humanize/bigbytes.go

@@ -0,0 +1,189 @@
+package humanize
+
+import (
+	"fmt"
+	"math/big"
+	"strings"
+	"unicode"
+)
+
+var (
+	bigIECExp = big.NewInt(1024)
+
+	// BigByte is one byte in bit.Ints
+	BigByte = big.NewInt(1)
+	// BigKiByte is 1,024 bytes in bit.Ints
+	BigKiByte = (&big.Int{}).Mul(BigByte, bigIECExp)
+	// BigMiByte is 1,024 k bytes in bit.Ints
+	BigMiByte = (&big.Int{}).Mul(BigKiByte, bigIECExp)
+	// BigGiByte is 1,024 m bytes in bit.Ints
+	BigGiByte = (&big.Int{}).Mul(BigMiByte, bigIECExp)
+	// BigTiByte is 1,024 g bytes in bit.Ints
+	BigTiByte = (&big.Int{}).Mul(BigGiByte, bigIECExp)
+	// BigPiByte is 1,024 t bytes in bit.Ints
+	BigPiByte = (&big.Int{}).Mul(BigTiByte, bigIECExp)
+	// BigEiByte is 1,024 p bytes in bit.Ints
+	BigEiByte = (&big.Int{}).Mul(BigPiByte, bigIECExp)
+	// BigZiByte is 1,024 e bytes in bit.Ints
+	BigZiByte = (&big.Int{}).Mul(BigEiByte, bigIECExp)
+	// BigYiByte is 1,024 z bytes in bit.Ints
+	BigYiByte = (&big.Int{}).Mul(BigZiByte, bigIECExp)
+	// BigRiByte is 1,024 y bytes in bit.Ints
+	BigRiByte = (&big.Int{}).Mul(BigYiByte, bigIECExp)
+	// BigQiByte is 1,024 r bytes in bit.Ints
+	BigQiByte = (&big.Int{}).Mul(BigRiByte, bigIECExp)
+)
+
+var (
+	bigSIExp = big.NewInt(1000)
+
+	// BigSIByte is one SI byte in big.Ints
+	BigSIByte = big.NewInt(1)
+	// BigKByte is 1,000 SI bytes in big.Ints
+	BigKByte = (&big.Int{}).Mul(BigSIByte, bigSIExp)
+	// BigMByte is 1,000 SI k bytes in big.Ints
+	BigMByte = (&big.Int{}).Mul(BigKByte, bigSIExp)
+	// BigGByte is 1,000 SI m bytes in big.Ints
+	BigGByte = (&big.Int{}).Mul(BigMByte, bigSIExp)
+	// BigTByte is 1,000 SI g bytes in big.Ints
+	BigTByte = (&big.Int{}).Mul(BigGByte, bigSIExp)
+	// BigPByte is 1,000 SI t bytes in big.Ints
+	BigPByte = (&big.Int{}).Mul(BigTByte, bigSIExp)
+	// BigEByte is 1,000 SI p bytes in big.Ints
+	BigEByte = (&big.Int{}).Mul(BigPByte, bigSIExp)
+	// BigZByte is 1,000 SI e bytes in big.Ints
+	BigZByte = (&big.Int{}).Mul(BigEByte, bigSIExp)
+	// BigYByte is 1,000 SI z bytes in big.Ints
+	BigYByte = (&big.Int{}).Mul(BigZByte, bigSIExp)
+	// BigRByte is 1,000 SI y bytes in big.Ints
+	BigRByte = (&big.Int{}).Mul(BigYByte, bigSIExp)
+	// BigQByte is 1,000 SI r bytes in big.Ints
+	BigQByte = (&big.Int{}).Mul(BigRByte, bigSIExp)
+)
+
+var bigBytesSizeTable = map[string]*big.Int{
+	"b":   BigByte,
+	"kib": BigKiByte,
+	"kb":  BigKByte,
+	"mib": BigMiByte,
+	"mb":  BigMByte,
+	"gib": BigGiByte,
+	"gb":  BigGByte,
+	"tib": BigTiByte,
+	"tb":  BigTByte,
+	"pib": BigPiByte,
+	"pb":  BigPByte,
+	"eib": BigEiByte,
+	"eb":  BigEByte,
+	"zib": BigZiByte,
+	"zb":  BigZByte,
+	"yib": BigYiByte,
+	"yb":  BigYByte,
+	"rib": BigRiByte,
+	"rb":  BigRByte,
+	"qib": BigQiByte,
+	"qb":  BigQByte,
+	// Without suffix
+	"":   BigByte,
+	"ki": BigKiByte,
+	"k":  BigKByte,
+	"mi": BigMiByte,
+	"m":  BigMByte,
+	"gi": BigGiByte,
+	"g":  BigGByte,
+	"ti": BigTiByte,
+	"t":  BigTByte,
+	"pi": BigPiByte,
+	"p":  BigPByte,
+	"ei": BigEiByte,
+	"e":  BigEByte,
+	"z":  BigZByte,
+	"zi": BigZiByte,
+	"y":  BigYByte,
+	"yi": BigYiByte,
+	"r":  BigRByte,
+	"ri": BigRiByte,
+	"q":  BigQByte,
+	"qi": BigQiByte,
+}
+
+var ten = big.NewInt(10)
+
+func humanateBigBytes(s, base *big.Int, sizes []string) string {
+	if s.Cmp(ten) < 0 {
+		return fmt.Sprintf("%d B", s)
+	}
+	c := (&big.Int{}).Set(s)
+	val, mag := oomm(c, base, len(sizes)-1)
+	suffix := sizes[mag]
+	f := "%.0f %s"
+	if val < 10 {
+		f = "%.1f %s"
+	}
+
+	return fmt.Sprintf(f, val, suffix)
+
+}
+
+// BigBytes produces a human readable representation of an SI size.
+//
+// See also: ParseBigBytes.
+//
+// BigBytes(82854982) -> 83 MB
+func BigBytes(s *big.Int) string {
+	sizes := []string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", "RB", "QB"}
+	return humanateBigBytes(s, bigSIExp, sizes)
+}
+
+// BigIBytes produces a human readable representation of an IEC size.
+//
+// See also: ParseBigBytes.
+//
+// BigIBytes(82854982) -> 79 MiB
+func BigIBytes(s *big.Int) string {
+	sizes := []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB", "RiB", "QiB"}
+	return humanateBigBytes(s, bigIECExp, sizes)
+}
+
+// ParseBigBytes parses a string representation of bytes into the number
+// of bytes it represents.
+//
+// See also: BigBytes, BigIBytes.
+//
+// ParseBigBytes("42 MB") -> 42000000, nil
+// ParseBigBytes("42 mib") -> 44040192, nil
+func ParseBigBytes(s string) (*big.Int, error) {
+	lastDigit := 0
+	hasComma := false
+	for _, r := range s {
+		if !(unicode.IsDigit(r) || r == '.' || r == ',') {
+			break
+		}
+		if r == ',' {
+			hasComma = true
+		}
+		lastDigit++
+	}
+
+	num := s[:lastDigit]
+	if hasComma {
+		num = strings.Replace(num, ",", "", -1)
+	}
+
+	val := &big.Rat{}
+	_, err := fmt.Sscanf(num, "%f", val)
+	if err != nil {
+		return nil, err
+	}
+
+	extra := strings.ToLower(strings.TrimSpace(s[lastDigit:]))
+	if m, ok := bigBytesSizeTable[extra]; ok {
+		mv := (&big.Rat{}).SetInt(m)
+		val.Mul(val, mv)
+		rv := &big.Int{}
+		rv.Div(val.Num(), val.Denom())
+		return rv, nil
+	}
+
+	return nil, fmt.Errorf("unhandled size name: %v", extra)
+}

vendor/github.com/dustin/go-humanize/bytes.go

@@ -0,0 +1,143 @@
+package humanize
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+// IEC Sizes.
+// kibis of bits
+const (
+	Byte = 1 << (iota * 10)
+	KiByte
+	MiByte
+	GiByte
+	TiByte
+	PiByte
+	EiByte
+)
+
+// SI Sizes.
+const (
+	IByte = 1
+	KByte = IByte * 1000
+	MByte = KByte * 1000
+	GByte = MByte * 1000
+	TByte = GByte * 1000
+	PByte = TByte * 1000
+	EByte = PByte * 1000
+)
+
+var bytesSizeTable = map[string]uint64{
+	"b":   Byte,
+	"kib": KiByte,
+	"kb":  KByte,
+	"mib": MiByte,
+	"mb":  MByte,
+	"gib": GiByte,
+	"gb":  GByte,
+	"tib": TiByte,
+	"tb":  TByte,
+	"pib": PiByte,
+	"pb":  PByte,
+	"eib": EiByte,
+	"eb":  EByte,
+	// Without suffix
+	"":   Byte,
+	"ki": KiByte,
+	"k":  KByte,
+	"mi": MiByte,
+	"m":  MByte,
+	"gi": GiByte,
+	"g":  GByte,
+	"ti": TiByte,
+	"t":  TByte,
+	"pi": PiByte,
+	"p":  PByte,
+	"ei": EiByte,
+	"e":  EByte,
+}
+
+func logn(n, b float64) float64 {
+	return math.Log(n) / math.Log(b)
+}
+
+func humanateBytes(s uint64, base float64, sizes []string) string {
+	if s < 10 {
+		return fmt.Sprintf("%d B", s)
+	}
+	e := math.Floor(logn(float64(s), base))
+	suffix := sizes[int(e)]
+	val := math.Floor(float64(s)/math.Pow(base, e)*10+0.5) / 10
+	f := "%.0f %s"
+	if val < 10 {
+		f = "%.1f %s"
+	}
+
+	return fmt.Sprintf(f, val, suffix)
+}
+
+// Bytes produces a human readable representation of an SI size.
+//
+// See also: ParseBytes.
+//
+// Bytes(82854982) -> 83 MB
+func Bytes(s uint64) string {
+	sizes := []string{"B", "kB", "MB", "GB", "TB", "PB", "EB"}
+	return humanateBytes(s, 1000, sizes)
+}
+
+// IBytes produces a human readable representation of an IEC size.
+//
+// See also: ParseBytes.
+//
+// IBytes(82854982) -> 79 MiB
+func IBytes(s uint64) string {
+	sizes := []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"}
+	return humanateBytes(s, 1024, sizes)
+}
+
+// ParseBytes parses a string representation of bytes into the number
+// of bytes it represents.
+//
+// See Also: Bytes, IBytes.
+//
+// ParseBytes("42 MB") -> 42000000, nil
+// ParseBytes("42 mib") -> 44040192, nil
+func ParseBytes(s string) (uint64, error) {
+	lastDigit := 0
+	hasComma := false
+	for _, r := range s {
+		if !(unicode.IsDigit(r) || r == '.' || r == ',') {
+			break
+		}
+		if r == ',' {
+			hasComma = true
+		}
+		lastDigit++
+	}
+
+	num := s[:lastDigit]
+	if hasComma {
+		num = strings.Replace(num, ",", "", -1)
+	}
+
+	f, err := strconv.ParseFloat(num, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	extra := strings.ToLower(strings.TrimSpace(s[lastDigit:]))
+	if m, ok := bytesSizeTable[extra]; ok {
+		f *= float64(m)
+		if f >= math.MaxUint64 {
+			return 0, fmt.Errorf("too large: %v", s)
+		}
+		return uint64(f), nil
+	}
+
+	return 0, fmt.Errorf("unhandled size name: %v", extra)
+}

vendor/github.com/dustin/go-humanize/comma.go

@@ -0,0 +1,116 @@
+package humanize
+
+import (
+	"bytes"
+	"math"
+	"math/big"
+	"strconv"
+	"strings"
+)
+
+// Comma produces a string form of the given number in base 10 with
+// commas after every three orders of magnitude.
+//
+// e.g. Comma(834142) -> 834,142
+func Comma(v int64) string {
+	sign := ""
+
+	// Min int64 can't be negated to a usable value, so it has to be special cased.
+	if v == math.MinInt64 {
+		return "-9,223,372,036,854,775,808"
+	}
+
+	if v < 0 {
+		sign = "-"
+		v = 0 - v
+	}
+
+	parts := []string{"", "", "", "", "", "", ""}
+	j := len(parts) - 1
+
+	for v > 999 {
+		parts[j] = strconv.FormatInt(v%1000, 10)
+		switch len(parts[j]) {
+		case 2:
+			parts[j] = "0" + parts[j]
+		case 1:
+			parts[j] = "00" + parts[j]
+		}
+		v = v / 1000
+		j--
+	}
+	parts[j] = strconv.Itoa(int(v))
+	return sign + strings.Join(parts[j:], ",")
+}
+
+// Commaf produces a string form of the given number in base 10 with
+// commas after every three orders of magnitude.
+//
+// e.g. Commaf(834142.32) -> 834,142.32
+func Commaf(v float64) string {
+	buf := &bytes.Buffer{}
+	if v < 0 {
+		buf.Write([]byte{'-'})
+		v = 0 - v
+	}
+
+	comma := []byte{','}
+
+	parts := strings.Split(strconv.FormatFloat(v, 'f', -1, 64), ".")
+	pos := 0
+	if len(parts[0])%3 != 0 {
+		pos += len(parts[0]) % 3
+		buf.WriteString(parts[0][:pos])
+		buf.Write(comma)
+	}
+	for ; pos < len(parts[0]); pos += 3 {
+		buf.WriteString(parts[0][pos : pos+3])
+		buf.Write(comma)
+	}
+	buf.Truncate(buf.Len() - 1)
+
+	if len(parts) > 1 {
+		buf.Write([]byte{'.'})
+		buf.WriteString(parts[1])
+	}
+	return buf.String()
+}
+
+// CommafWithDigits works like the Commaf but limits the resulting
+// string to the given number of decimal places.
+//
+// e.g. CommafWithDigits(834142.32, 1) -> 834,142.3
+func CommafWithDigits(f float64, decimals int) string {
+	return stripTrailingDigits(Commaf(f), decimals)
+}
+
+// BigComma produces a string form of the given big.Int in base 10
+// with commas after every three orders of magnitude.
+func BigComma(b *big.Int) string {
+	sign := ""
+	if b.Sign() < 0 {
+		sign = "-"
+		b.Abs(b)
+	}
+
+	athousand := big.NewInt(1000)
+	c := (&big.Int{}).Set(b)
+	_, m := oom(c, athousand)
+	parts := make([]string, m+1)
+	j := len(parts) - 1
+
+	mod := &big.Int{}
+	for b.Cmp(athousand) >= 0 {
+		b.DivMod(b, athousand, mod)
+		parts[j] = strconv.FormatInt(mod.Int64(), 10)
+		switch len(parts[j]) {
+		case 2:
+			parts[j] = "0" + parts[j]
+		case 1:
+			parts[j] = "00" + parts[j]
+		}
+		j--
+	}
+	parts[j] = strconv.Itoa(int(b.Int64()))
+	return sign + strings.Join(parts[j:], ",")
+}