Updated Readme files

README.md

@@ -16,19 +16,47 @@ RelSpec provides bidirectional conversion and comparison between various databas
 
 ## Features
 
-### Input Formats
-- **XML** - Generic XML schema definitions
-- **JSON** - JSON-based schema specifications
-- **Clarion DCTX** - Clarion database dictionary format
-- **Database Inspection** - Direct database introspection
-- **GORM Models** - Read existing GORM Go structs
-- **Bun Models** - Read existing Bun Go structs
+### Readers (Input Formats)
 
-### Output Formats
-- **GORM Models** - Generate GORM-compatible Go structs
-- **Bun Models** - Generate Bun-compatible Go structs
-- **JSON** - Standard JSON schema output
-- **YAML** - Human-readable YAML format
+RelSpec can read database schemas from multiple sources:
+
+#### ORM Models
+- [GORM](pkg/readers/gorm/README.md) - Go GORM model definitions
+- [Bun](pkg/readers/bun/README.md) - Go Bun model definitions
+- [Drizzle](pkg/readers/drizzle/README.md) - TypeScript Drizzle ORM schemas
+- [Prisma](pkg/readers/prisma/README.md) - Prisma schema language
+- [TypeORM](pkg/readers/typeorm/README.md) - TypeScript TypeORM entities
+
+#### Database Inspection
+- [PostgreSQL](pkg/readers/pgsql/README.md) - Direct PostgreSQL database introspection
+
+#### Schema Formats
+- [DBML](pkg/readers/dbml/README.md) - Database Markup Language (dbdiagram.io)
+- [DCTX](pkg/readers/dctx/README.md) - Clarion database dictionary format
+- [DrawDB](pkg/readers/drawdb/README.md) - DrawDB JSON format
+- [JSON](pkg/readers/json/README.md) - RelSpec canonical JSON format
+- [YAML](pkg/readers/yaml/README.md) - RelSpec canonical YAML format
+
+### Writers (Output Formats)
+
+RelSpec can write database schemas to multiple formats:
+
+#### ORM Models
+- [GORM](pkg/writers/gorm/README.md) - Generate GORM-compatible Go structs
+- [Bun](pkg/writers/bun/README.md) - Generate Bun-compatible Go structs
+- [Drizzle](pkg/writers/drizzle/README.md) - Generate Drizzle ORM TypeScript schemas
+- [Prisma](pkg/writers/prisma/README.md) - Generate Prisma schema files
+- [TypeORM](pkg/writers/typeorm/README.md) - Generate TypeORM TypeScript entities
+
+#### Database DDL
+- [PostgreSQL](pkg/writers/pgsql/README.md) - PostgreSQL DDL (CREATE TABLE, etc.)
+
+#### Schema Formats
+- [DBML](pkg/writers/dbml/README.md) - Database Markup Language
+- [DCTX](pkg/writers/dctx/README.md) - Clarion database dictionary format
+- [DrawDB](pkg/writers/drawdb/README.md) - DrawDB JSON format
+- [JSON](pkg/writers/json/README.md) - RelSpec canonical JSON format
+- [YAML](pkg/writers/yaml/README.md) - RelSpec canonical YAML format
 
 
 ## Use of AI
@@ -98,7 +126,7 @@ go test ./...
 
 Apache License 2.0 - See [LICENSE](LICENSE) for details.
 
-Copyright 2025 wdevs
+Copyright 2025 Warky Devs
 
 ## Contributing
 

pkg/readers/bun/README.md

@@ -0,0 +1,106 @@
+# Bun Reader
+
+Reads Go source files containing Bun model definitions and extracts database schema information.
+
+## Overview
+
+The Bun Reader parses Go source code files that define Bun models (structs with `bun` struct tags) and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses Bun struct tags to extract column definitions
+- Extracts table names from `bun:"table:tablename"` tags
+- Identifies primary keys, foreign keys, and indexes
+- Supports relationship detection
+- Handles both single files and directories
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/bun"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/models.go",
+    }
+
+    reader := bun.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read Bun models and convert to JSON
+relspec --input bun --in-file models/ --output json --out-file schema.json
+
+# Convert Bun models to GORM
+relspec --input bun --in-file models.go --output gorm --out-file gorm_models.go
+```
+
+## Supported Bun Tags
+
+The reader recognizes the following Bun struct tags:
+
+- `table` - Table name
+- `column` - Column name
+- `type` - SQL data type
+- `pk` - Primary key
+- `notnull` - NOT NULL constraint
+- `autoincrement` - Auto-increment column
+- `default` - Default value
+- `unique` - Unique constraint
+- `rel` - Relationship definition
+
+## Example Bun Model
+
+```go
+package models
+
+import (
+    "time"
+    "github.com/uptrace/bun"
+)
+
+type User struct {
+    bun.BaseModel `bun:"table:users,alias:u"`
+
+    ID        int64     `bun:"id,pk,autoincrement"`
+    Username  string    `bun:"username,notnull,unique"`
+    Email     string    `bun:"email,notnull"`
+    CreatedAt time.Time `bun:"created_at,notnull,default:now()"`
+
+    Posts []*Post `bun:"rel:has-many,join:id=user_id"`
+}
+
+type Post struct {
+    bun.BaseModel `bun:"table:posts,alias:p"`
+
+    ID      int64  `bun:"id,pk"`
+    UserID  int64  `bun:"user_id,notnull"`
+    Title   string `bun:"title,notnull"`
+    Content string `bun:"content"`
+
+    User *User `bun:"rel:belongs-to,join:user_id=id"`
+}
+```
+
+## Notes
+
+- Test files (ending in `_test.go`) are automatically excluded
+- The `bun.BaseModel` embedded struct is automatically recognized
+- Schema defaults to `public` if not specified

pkg/readers/dbml/README.md

@@ -0,0 +1,101 @@
+# DBML Reader
+
+Reads Database Markup Language (DBML) files and extracts database schema information.
+
+## Overview
+
+The DBML Reader parses `.dbml` files that define database schemas using the DBML syntax (used by dbdiagram.io) and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses DBML syntax
+- Extracts tables, columns, and relationships
+- Supports DBML-specific features:
+  - Table groups and notes
+  - Enum definitions
+  - Indexes
+  - Foreign key relationships
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.dbml",
+    }
+
+    reader := dbml.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read DBML file and convert to JSON
+relspec --input dbml --in-file schema.dbml --output json --out-file schema.json
+
+# Convert DBML to GORM models
+relspec --input dbml --in-file database.dbml --output gorm --out-file models.go
+```
+
+## Example DBML File
+
+```dbml
+Table users {
+  id bigserial [pk, increment]
+  username varchar(50) [not null, unique]
+  email varchar(100) [not null]
+  created_at timestamp [not null, default: `now()`]
+
+  Note: 'Users table'
+}
+
+Table posts {
+  id bigserial [pk]
+  user_id bigint [not null, ref: > users.id]
+  title varchar(200) [not null]
+  content text
+
+  indexes {
+    user_id
+    (user_id, created_at) [name: 'idx_user_posts']
+  }
+}
+
+Ref: posts.user_id > users.id [delete: cascade]
+```
+
+## DBML Features Supported
+
+- Table definitions with columns
+- Primary keys (`pk`)
+- Not null constraints (`not null`)
+- Unique constraints (`unique`)
+- Default values (`default`)
+- Inline references (`ref`)
+- Standalone `Ref` blocks
+- Indexes and composite indexes
+- Table notes and column notes
+- Enums
+
+## Notes
+
+- DBML is designed for database documentation and diagramming
+- Schema name defaults to `public`
+- Relationship cardinality is preserved

pkg/readers/dctx/README.md

@@ -0,0 +1,96 @@
+# DCTX Reader
+
+Reads Clarion database dictionary (DCTX) files and extracts database schema information.
+
+## Overview
+
+The DCTX Reader parses Clarion dictionary files (`.dctx`) that define database structures in the Clarion development system and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses Clarion DCTX XML format
+- Extracts file (table) and field (column) definitions
+- Supports Clarion data types
+- Handles keys (indexes) and relationships
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/dctx"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/database.dctx",
+    }
+
+    reader := dctx.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read DCTX file and convert to JSON
+relspec --input dctx --in-file legacy.dctx --output json --out-file schema.json
+
+# Convert DCTX to GORM models for migration
+relspec --input dctx --in-file app.dctx --output gorm --out-file models.go
+
+# Export DCTX to PostgreSQL DDL
+relspec --input dctx --in-file database.dctx --output pgsql --out-file schema.sql
+```
+
+## Example DCTX Structure
+
+DCTX files are XML-based Clarion dictionary files that define:
+
+- Files (equivalent to tables)
+- Fields (columns) with Clarion-specific types
+- Keys (indexes)
+- Relationships between files
+
+Common Clarion data types:
+- `STRING` - Fixed-length string
+- `CSTRING` - C-style null-terminated string
+- `LONG` - 32-bit integer
+- `SHORT` - 16-bit integer
+- `DECIMAL` - Decimal number
+- `REAL` - Floating point
+- `DATE` - Date field
+- `TIME` - Time field
+
+## Type Mapping
+
+The reader automatically maps Clarion data types to standard SQL types:
+
+| Clarion Type | SQL Type |
+|--------------|----------|
+| STRING | VARCHAR |
+| CSTRING | VARCHAR |
+| LONG | INTEGER |
+| SHORT | SMALLINT |
+| DECIMAL | NUMERIC |
+| REAL | REAL |
+| DATE | DATE |
+| TIME | TIME |
+
+## Notes
+
+- DCTX is specific to Clarion development platform
+- Useful for migrating legacy Clarion applications
+- Schema name defaults to `public`
+- Preserves field properties and constraints where possible

pkg/readers/drawdb/README.md

@@ -0,0 +1,96 @@
+# DrawDB Reader
+
+Reads DrawDB schema files and extracts database schema information.
+
+## Overview
+
+The DrawDB Reader parses JSON files exported from DrawDB (a free online database design tool) and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses DrawDB JSON format
+- Extracts tables, fields, and relationships
+- Supports DrawDB-specific metadata
+- Preserves visual layout information
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/drawdb"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/diagram.json",
+    }
+
+    reader := drawdb.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read DrawDB export and convert to JSON schema
+relspec --input drawdb --in-file diagram.json --output json --out-file schema.json
+
+# Convert DrawDB design to GORM models
+relspec --input drawdb --in-file design.json --output gorm --out-file models.go
+```
+
+## Example DrawDB Export
+
+DrawDB exports database designs as JSON files containing:
+
+```json
+{
+  "tables": [
+    {
+      "id": "1",
+      "name": "users",
+      "fields": [
+        {
+          "name": "id",
+          "type": "BIGINT",
+          "primary": true,
+          "autoIncrement": true
+        },
+        {
+          "name": "username",
+          "type": "VARCHAR",
+          "size": 50,
+          "notNull": true,
+          "unique": true
+        }
+      ]
+    }
+  ],
+  "relationships": [
+    {
+      "source": "posts",
+      "target": "users",
+      "type": "many-to-one"
+    }
+  ]
+}
+```
+
+## Notes
+
+- DrawDB is a free online database designer at drawdb.vercel.app
+- Export format preserves visual design metadata
+- Useful for converting visual designs to code
+- Schema defaults to `public`

pkg/readers/drizzle/README.md

@@ -0,0 +1,90 @@
+# Drizzle Reader
+
+Reads TypeScript/JavaScript files containing Drizzle ORM schema definitions and extracts database schema information.
+
+## Overview
+
+The Drizzle Reader parses Drizzle ORM schema files (TypeScript/JavaScript) that define database tables using Drizzle's schema builder and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses Drizzle schema definitions
+- Extracts table, column, and relationship information
+- Supports various Drizzle column types
+- Handles constraints and indexes
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/drizzle"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.ts",
+    }
+
+    reader := drizzle.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read Drizzle schema and convert to JSON
+relspec --input drizzle --in-file schema.ts --output json --out-file schema.json
+
+# Convert Drizzle to GORM models
+relspec --input drizzle --in-file schema/ --output gorm --out-file models.go
+```
+
+## Example Drizzle Schema
+
+```typescript
+import { pgTable, serial, varchar, text, timestamp, integer } from 'drizzle-orm/pg-core';
+import { relations } from 'drizzle-orm';
+
+export const users = pgTable('users', {
+  id: serial('id').primaryKey(),
+  username: varchar('username', { length: 50 }).notNull().unique(),
+  email: varchar('email', { length: 100 }).notNull(),
+  createdAt: timestamp('created_at').notNull().defaultNow(),
+});
+
+export const posts = pgTable('posts', {
+  id: serial('id').primaryKey(),
+  userId: integer('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
+  title: varchar('title', { length: 200 }).notNull(),
+  content: text('content'),
+});
+
+export const usersRelations = relations(users, ({ many }) => ({
+  posts: many(posts),
+}));
+
+export const postsRelations = relations(posts, ({ one }) => ({
+  user: one(users, {
+    fields: [posts.userId],
+    references: [users.id],
+  }),
+}));
+```
+
+## Notes
+
+- Supports both PostgreSQL and MySQL Drizzle schemas
+- Extracts relationship information from `relations` definitions
+- Schema defaults to `public` for PostgreSQL

pkg/readers/gorm/README.md

@@ -0,0 +1,141 @@
+# GORM Reader
+
+Reads Go source files containing GORM model definitions and extracts database schema information.
+
+## Overview
+
+The GORM Reader parses Go source code files that define GORM models (structs with `gorm` struct tags) and converts them into RelSpec's internal database model representation. It supports reading from individual files or entire directories.
+
+## Features
+
+- Parses GORM struct tags to extract column definitions
+- Extracts table names from `TableName()` methods
+- Identifies primary keys, foreign keys, and indexes
+- Supports relationship detection (has-many, belongs-to)
+- Handles both single files and directories
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/gorm"
+)
+
+func main() {
+    // Read from a single file
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/models.go",
+    }
+
+    reader := gorm.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### Reading from Directory
+
+```go
+// Read all .go files from a directory
+options := &readers.ReaderOptions{
+    FilePath: "/path/to/models/",
+}
+
+reader := gorm.NewReader(options)
+db, err := reader.ReadDatabase()
+if err != nil {
+    panic(err)
+}
+```
+
+### CLI Example
+
+```bash
+# Read GORM models and convert to JSON
+relspec --input gorm --in-file models/ --output json --out-file schema.json
+
+# Convert GORM models to Bun
+relspec --input gorm --in-file models.go --output bun --out-file bun_models.go
+```
+
+## Supported GORM Tags
+
+The reader recognizes the following GORM struct tags:
+
+- `column` - Column name
+- `type` - SQL data type (e.g., `varchar(255)`, `bigint`)
+- `primaryKey` or `primary_key` - Mark as primary key
+- `not null` - NOT NULL constraint
+- `autoIncrement` - Auto-increment column
+- `default` - Default value
+- `size` - Column size/length
+- `index` - Create index
+- `uniqueIndex` - Create unique index
+- `unique` - Unique constraint
+- `foreignKey` - Foreign key column
+- `references` - Referenced column
+- `constraint` - Constraint behavior (OnDelete, OnUpdate)
+
+## Example GORM Model
+
+```go
+package models
+
+import (
+    "time"
+    "gorm.io/gorm"
+)
+
+type ModelUser struct {
+    gorm.Model
+    ID        int64  `gorm:"column:id;type:bigint;primaryKey;autoIncrement"`
+    Username  string `gorm:"column:username;type:varchar(50);not null;uniqueIndex"`
+    Email     string `gorm:"column:email;type:varchar(100);not null"`
+    CreatedAt time.Time `gorm:"column:created_at;type:timestamp;not null;default:now()"`
+
+    // Relationships
+    Posts []*ModelPost `gorm:"foreignKey:UserID;references:ID;constraint:OnDelete:CASCADE"`
+}
+
+func (ModelUser) TableName() string {
+    return "public.users"
+}
+
+type ModelPost struct {
+    ID        int64  `gorm:"column:id;type:bigint;primaryKey"`
+    UserID    int64  `gorm:"column:user_id;type:bigint;not null"`
+    Title     string `gorm:"column:title;type:varchar(200);not null"`
+    Content   string `gorm:"column:content;type:text"`
+
+    // Belongs-to relationship
+    User *ModelUser `gorm:"foreignKey:UserID;references:ID"`
+}
+
+func (ModelPost) TableName() string {
+    return "public.posts"
+}
+```
+
+## Notes
+
+- Test files (ending in `_test.go`) are automatically excluded
+- The `gorm.Model` embedded struct is automatically recognized and skipped
+- Table names are derived from struct names if `TableName()` method is not present
+- Schema defaults to `public` if not specified in `TableName()`
+- Relationships are inferred from GORM relationship tags
+
+## Limitations
+
+- Complex relationship types (many-to-many with join tables) may need manual verification
+- Custom GORM types may not be fully supported
+- Some advanced GORM features may not be captured

pkg/readers/json/README.md

@@ -0,0 +1,152 @@
+# JSON Reader
+
+Reads database schema definitions from JSON files.
+
+## Overview
+
+The JSON Reader parses JSON files that define database schemas in RelSpec's canonical JSON format and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Reads RelSpec's standard JSON schema format
+- Supports complete schema representation including:
+  - Databases and schemas
+  - Tables, columns, and data types
+  - Constraints (PK, FK, unique, check)
+  - Indexes
+  - Relationships
+  - Views and sequences
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/json"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.json",
+    }
+
+    reader := json.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read JSON schema and convert to GORM models
+relspec --input json --in-file schema.json --output gorm --out-file models.go
+
+# Convert JSON to PostgreSQL DDL
+relspec --input json --in-file database.json --output pgsql --out-file schema.sql
+
+# Transform JSON to YAML
+relspec --input json --in-file schema.json --output yaml --out-file schema.yaml
+```
+
+## Example JSON Schema
+
+```json
+{
+  "name": "myapp",
+  "database_type": "postgresql",
+  "schemas": [
+    {
+      "name": "public",
+      "tables": [
+        {
+          "name": "users",
+          "schema": "public",
+          "columns": {
+            "id": {
+              "name": "id",
+              "type": "bigint",
+              "not_null": true,
+              "is_primary_key": true,
+              "auto_increment": true,
+              "sequence": 1
+            },
+            "username": {
+              "name": "username",
+              "type": "varchar",
+              "length": 50,
+              "not_null": true,
+              "sequence": 2
+            },
+            "email": {
+              "name": "email",
+              "type": "varchar",
+              "length": 100,
+              "not_null": true,
+              "sequence": 3
+            }
+          },
+          "constraints": {
+            "pk_users": {
+              "name": "pk_users",
+              "type": "PRIMARY KEY",
+              "columns": ["id"]
+            },
+            "uq_users_username": {
+              "name": "uq_users_username",
+              "type": "UNIQUE",
+              "columns": ["username"]
+            }
+          },
+          "indexes": {
+            "idx_users_email": {
+              "name": "idx_users_email",
+              "columns": ["email"],
+              "unique": false,
+              "type": "btree"
+            }
+          }
+        }
+      ]
+    }
+  ]
+}
+```
+
+## Schema Structure
+
+The JSON format follows RelSpec's internal model structure:
+
+- `Database` - Top-level container
+  - `name` - Database name
+  - `database_type` - Database system (postgresql, mysql, etc.)
+  - `schemas[]` - Array of schemas
+
+- `Schema` - Schema/namespace
+  - `name` - Schema name
+  - `tables[]` - Array of tables
+  - `views[]` - Array of views
+  - `sequences[]` - Array of sequences
+
+- `Table` - Table definition
+  - `name` - Table name
+  - `columns{}` - Map of columns
+  - `constraints{}` - Map of constraints
+  - `indexes{}` - Map of indexes
+  - `relationships{}` - Map of relationships
+
+## Notes
+
+- This is RelSpec's native interchange format
+- Preserves complete schema information
+- Ideal for version control and schema documentation
+- Can be used as an intermediate format for transformations

pkg/readers/pgsql/README.md

@@ -0,0 +1,138 @@
+# PostgreSQL Reader
+
+Reads schema information directly from a live PostgreSQL database.
+
+## Overview
+
+The PostgreSQL Reader connects to a PostgreSQL database and introspects its schema, extracting complete information about tables, columns, constraints, indexes, views, and sequences.
+
+## Features
+
+- Direct database introspection
+- Extracts complete schema information including:
+  - Tables and columns
+  - Primary keys, foreign keys, unique constraints, check constraints
+  - Indexes
+  - Views
+  - Sequences
+- Supports multiple schemas
+- Captures constraint actions (ON DELETE, ON UPDATE)
+- Derives relationships from foreign keys
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/pgsql"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        ConnectionString: "postgres://user:password@localhost:5432/mydb?sslmode=disable",
+    }
+
+    reader := pgsql.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Database: %s\n", db.Name)
+    fmt.Printf("Schemas: %d\n", len(db.Schemas))
+    for _, schema := range db.Schemas {
+        fmt.Printf("  Schema: %s, Tables: %d\n", schema.Name, len(schema.Tables))
+    }
+}
+```
+
+### CLI Example
+
+```bash
+# Inspect PostgreSQL database and export to JSON
+relspec --input pgsql \
+  --conn "postgres://user:password@localhost:5432/mydb" \
+  --output json \
+  --out-file schema.json
+
+# Generate GORM models from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://user:password@localhost:5432/mydb" \
+  --output gorm \
+  --out-file models.go
+
+# Export database structure to YAML
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb?sslmode=disable" \
+  --output yaml \
+  --out-file schema.yaml
+```
+
+## Connection String Format
+
+The reader uses PostgreSQL connection strings in the format:
+
+```
+postgres://username:password@hostname:port/database?parameters
+```
+
+Examples:
+```
+postgres://localhost/mydb
+postgres://user:pass@localhost:5432/mydb
+postgres://user@localhost/mydb?sslmode=disable
+postgres://user:pass@db.example.com:5432/production?sslmode=require
+```
+
+## Extracted Information
+
+### Tables
+- Table name and schema
+- Comments/descriptions
+- All columns with data types, nullable, defaults
+- Sequences
+
+### Columns
+- Column name, data type, length/precision
+- NULL/NOT NULL constraints
+- Default values
+- Auto-increment information
+- Primary key designation
+
+### Constraints
+- Primary keys
+- Foreign keys (with ON DELETE/UPDATE actions)
+- Unique constraints
+- Check constraints
+
+### Indexes
+- Index name and type (btree, hash, gist, gin, etc.)
+- Columns in index
+- Unique/non-unique
+- Partial indexes
+
+### Views
+- View definitions
+- Column information
+
+### Sequences
+- Sequence properties
+- Associated tables
+
+## Notes
+
+- Requires PostgreSQL connection permissions
+- Reads all non-system schemas (excludes pg_catalog, information_schema, pg_toast)
+- Captures PostgreSQL-specific data types
+- Automatically maps PostgreSQL types to canonical types
+- Preserves relationship metadata for downstream conversion
+
+## Requirements
+
+- Go library: `github.com/jackc/pgx/v5`
+- Database user must have SELECT permissions on system catalogs

pkg/readers/prisma/README.md

@@ -0,0 +1,103 @@
+# Prisma Reader
+
+Reads Prisma schema files and extracts database schema information.
+
+## Overview
+
+The Prisma Reader parses `.prisma` schema files that define database models using Prisma's schema language and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses Prisma schema syntax
+- Extracts models, fields, and relationships
+- Supports Prisma attributes and directives
+- Handles enums and composite types
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/prisma"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.prisma",
+    }
+
+    reader := prisma.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read Prisma schema and convert to JSON
+relspec --input prisma --in-file schema.prisma --output json --out-file schema.json
+
+# Convert Prisma to GORM models
+relspec --input prisma --in-file schema.prisma --output gorm --out-file models.go
+```
+
+## Example Prisma Schema
+
+```prisma
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+model User {
+  id        Int      @id @default(autoincrement())
+  username  String   @unique @db.VarChar(50)
+  email     String   @db.VarChar(100)
+  createdAt DateTime @default(now()) @map("created_at")
+
+  posts Post[]
+
+  @@map("users")
+}
+
+model Post {
+  id      Int    @id @default(autoincrement())
+  userId  Int    @map("user_id")
+  title   String @db.VarChar(200)
+  content String @db.Text
+
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@map("posts")
+}
+```
+
+## Supported Prisma Attributes
+
+- `@id` - Primary key
+- `@unique` - Unique constraint
+- `@default` - Default value
+- `@map` - Column name mapping
+- `@@map` - Table name mapping
+- `@relation` - Relationship definition
+- `@db.*` - Database-specific type annotations
+
+## Notes
+
+- Extracts datasource provider information
+- Supports `@@map` for custom table names
+- Handles Prisma-specific types and converts them to standard SQL types

pkg/readers/typeorm/README.md

@@ -0,0 +1,122 @@
+# TypeORM Reader
+
+Reads TypeScript files containing TypeORM entity definitions and extracts database schema information.
+
+## Overview
+
+The TypeORM Reader parses TypeScript source files that define TypeORM entities (classes with TypeORM decorators) and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Parses TypeORM decorators and entity definitions
+- Extracts table, column, and relationship information
+- Supports various TypeORM column types and options
+- Handles constraints, indexes, and relationships
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/typeorm"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/entities/",
+    }
+
+    reader := typeorm.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read TypeORM entities and convert to JSON
+relspec --input typeorm --in-file entities/ --output json --out-file schema.json
+
+# Convert TypeORM to GORM models
+relspec --input typeorm --in-file User.ts --output gorm --out-file models.go
+```
+
+## Example TypeORM Entity
+
+```typescript
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  OneToMany,
+} from 'typeorm';
+import { Post } from './Post';
+
+@Entity('users')
+export class User {
+  @PrimaryGeneratedColumn('increment')
+  id: number;
+
+  @Column({ type: 'varchar', length: 50, unique: true })
+  username: string;
+
+  @Column({ type: 'varchar', length: 100 })
+  email: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @OneToMany(() => Post, (post) => post.user)
+  posts: Post[];
+}
+
+@Entity('posts')
+export class Post {
+  @PrimaryGeneratedColumn('increment')
+  id: number;
+
+  @Column({ name: 'user_id' })
+  userId: number;
+
+  @Column({ type: 'varchar', length: 200 })
+  title: string;
+
+  @Column({ type: 'text' })
+  content: string;
+
+  @ManyToOne(() => User, (user) => user.posts, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'user_id' })
+  user: User;
+}
+```
+
+## Supported TypeORM Decorators
+
+- `@Entity()` - Entity/table definition
+- `@PrimaryGeneratedColumn()` - Auto-increment primary key
+- `@PrimaryColumn()` - Primary key
+- `@Column()` - Column definition
+- `@CreateDateColumn()` - Auto-set creation timestamp
+- `@UpdateDateColumn()` - Auto-update timestamp
+- `@OneToMany()` - One-to-many relationship
+- `@ManyToOne()` - Many-to-one relationship
+- `@JoinColumn()` - Foreign key column
+- `@Index()` - Index definition
+- `@Unique()` - Unique constraint
+
+## Notes
+
+- Schema name can be specified in `@Entity()` decorator
+- Supports both JavaScript and TypeScript entity files
+- Relationship metadata is extracted from decorators

pkg/readers/yaml/README.md

@@ -0,0 +1,159 @@
+# YAML Reader
+
+Reads database schema definitions from YAML files.
+
+## Overview
+
+The YAML Reader parses YAML files that define database schemas in RelSpec's canonical YAML format and converts them into RelSpec's internal database model representation.
+
+## Features
+
+- Reads RelSpec's standard YAML schema format
+- Human-readable alternative to JSON format
+- Supports complete schema representation including:
+  - Databases and schemas
+  - Tables, columns, and data types
+  - Constraints (PK, FK, unique, check)
+  - Indexes
+  - Relationships
+  - Views and sequences
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
+)
+
+func main() {
+    options := &readers.ReaderOptions{
+        FilePath: "/path/to/schema.yaml",
+    }
+
+    reader := yaml.NewReader(options)
+    db, err := reader.ReadDatabase()
+    if err != nil {
+        panic(err)
+    }
+
+    fmt.Printf("Found %d schemas\n", len(db.Schemas))
+}
+```
+
+### CLI Example
+
+```bash
+# Read YAML schema and convert to GORM models
+relspec --input yaml --in-file schema.yaml --output gorm --out-file models.go
+
+# Convert YAML to PostgreSQL DDL
+relspec --input yaml --in-file database.yaml --output pgsql --out-file schema.sql
+
+# Transform YAML to JSON
+relspec --input yaml --in-file schema.yaml --output json --out-file schema.json
+```
+
+## Example YAML Schema
+
+```yaml
+name: myapp
+database_type: postgresql
+schemas:
+  - name: public
+    tables:
+      - name: users
+        schema: public
+        columns:
+          id:
+            name: id
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            auto_increment: true
+            sequence: 1
+          username:
+            name: username
+            type: varchar
+            length: 50
+            not_null: true
+            sequence: 2
+          email:
+            name: email
+            type: varchar
+            length: 100
+            not_null: true
+            sequence: 3
+        constraints:
+          pk_users:
+            name: pk_users
+            type: PRIMARY KEY
+            columns:
+              - id
+          uq_users_username:
+            name: uq_users_username
+            type: UNIQUE
+            columns:
+              - username
+        indexes:
+          idx_users_email:
+            name: idx_users_email
+            columns:
+              - email
+            unique: false
+            type: btree
+      - name: posts
+        schema: public
+        columns:
+          id:
+            name: id
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            sequence: 1
+          user_id:
+            name: user_id
+            type: bigint
+            not_null: true
+            sequence: 2
+          title:
+            name: title
+            type: varchar
+            length: 200
+            not_null: true
+            sequence: 3
+        constraints:
+          fk_posts_user_id:
+            name: fk_posts_user_id
+            type: FOREIGN KEY
+            columns:
+              - user_id
+            referenced_table: users
+            referenced_schema: public
+            referenced_columns:
+              - id
+            on_delete: CASCADE
+            on_update: NO ACTION
+```
+
+## Schema Structure
+
+The YAML format mirrors RelSpec's internal model structure with human-readable syntax:
+
+- Database level: `name`, `database_type`, `schemas`
+- Schema level: `name`, `tables`, `views`, `sequences`
+- Table level: `name`, `schema`, `columns`, `constraints`, `indexes`, `relationships`
+- Column level: `name`, `type`, `length`, `not_null`, `default`, etc.
+
+## Notes
+
+- YAML format is more human-readable than JSON
+- Ideal for manual editing and version control
+- Comments are supported in YAML
+- Preserves complete schema information
+- Can be used for configuration and documentation

pkg/writers/bun/README.md

@@ -0,0 +1,129 @@
+# Bun Writer
+
+Generates Go source files with Bun model definitions from database schema information.
+
+## Overview
+
+The Bun Writer converts RelSpec's internal database model representation into Go source code with Bun struct definitions, complete with proper tags, relationships, and table configuration.
+
+## Features
+
+- Generates Bun-compatible Go structs
+- Creates proper `bun` struct tags
+- Adds relationship fields
+- Supports both single-file and multi-file output
+- Maps SQL types to Go types
+- Handles nullable fields with sql.Null* types
+- Generates table aliases
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/bun"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath:  "models.go",
+        PackageName: "models",
+    }
+
+    writer := bun.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate Bun models from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output bun \
+  --out-file models.go \
+  --package models
+
+# Convert GORM models to Bun
+relspec --input gorm --in-file gorm_models.go --output bun --out-file bun_models.go
+
+# Multi-file output
+relspec --input json --in-file schema.json --output bun --out-file models/
+```
+
+## Generated Code Example
+
+```go
+package models
+
+import (
+    "time"
+    "database/sql"
+    "github.com/uptrace/bun"
+)
+
+type User struct {
+    bun.BaseModel `bun:"table:users,alias:u"`
+
+    ID        int64     `bun:"id,pk,autoincrement" json:"id"`
+    Username  string    `bun:"username,notnull,unique" json:"username"`
+    Email     string    `bun:"email,notnull" json:"email"`
+    Bio       sql.NullString `bun:"bio" json:"bio,omitempty"`
+    CreatedAt time.Time `bun:"created_at,notnull,default:now()" json:"created_at"`
+
+    // Relationships
+    Posts []*Post `bun:"rel:has-many,join:id=user_id" json:"posts,omitempty"`
+}
+
+type Post struct {
+    bun.BaseModel `bun:"table:posts,alias:p"`
+
+    ID      int64          `bun:"id,pk" json:"id"`
+    UserID  int64          `bun:"user_id,notnull" json:"user_id"`
+    Title   string         `bun:"title,notnull" json:"title"`
+    Content sql.NullString `bun:"content" json:"content,omitempty"`
+
+    // Belongs to
+    User *User `bun:"rel:belongs-to,join:user_id=id" json:"user,omitempty"`
+}
+```
+
+## Supported Bun Tags
+
+- `table` - Table name and alias
+- `column` - Column name (auto-derived if not specified)
+- `pk` - Primary key
+- `autoincrement` - Auto-increment
+- `notnull` - NOT NULL constraint
+- `unique` - Unique constraint
+- `default` - Default value
+- `rel` - Relationship definition
+- `type` - Explicit SQL type
+
+## Type Mapping
+
+| SQL Type | Go Type | Nullable Type |
+|----------|---------|---------------|
+| bigint | int64 | sql.NullInt64 |
+| integer | int | sql.NullInt32 |
+| varchar, text | string | sql.NullString |
+| boolean | bool | sql.NullBool |
+| timestamp | time.Time | sql.NullTime |
+| numeric | float64 | sql.NullFloat64 |
+
+## Notes
+
+- Model names are derived from table names (singularized, PascalCase)
+- Table aliases are auto-generated from table names
+- Multi-file mode: one file per table named `sql_{schema}_{table}.go`
+- Generated code is auto-formatted
+- JSON tags are automatically added

pkg/writers/dbml/README.md

@@ -0,0 +1,161 @@
+# DBML Writer
+
+Generates Database Markup Language (DBML) files from database schema information.
+
+## Overview
+
+The DBML Writer converts RelSpec's internal database model representation into DBML syntax, suitable for use with dbdiagram.io and other DBML-compatible tools.
+
+## Features
+
+- Generates DBML syntax
+- Creates table definitions with columns
+- Defines relationships
+- Includes indexes
+- Adds notes and documentation
+- Supports enums
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/dbml"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.dbml",
+    }
+
+    writer := dbml.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate DBML from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output dbml \
+  --out-file schema.dbml
+
+# Convert GORM models to DBML
+relspec --input gorm --in-file models.go --output dbml --out-file database.dbml
+
+# Convert JSON to DBML for visualization
+relspec --input json --in-file schema.json --output dbml --out-file diagram.dbml
+```
+
+## Generated DBML Example
+
+```dbml
+Project MyDatabase {
+  database_type: 'PostgreSQL'
+}
+
+Table users {
+  id bigserial [pk, increment]
+  username varchar(50) [not null, unique]
+  email varchar(100) [not null]
+  bio text [null]
+  created_at timestamp [not null, default: `now()`]
+
+  Note: 'Users table'
+
+  indexes {
+    email [name: 'idx_users_email']
+  }
+}
+
+Table posts {
+  id bigserial [pk, increment]
+  user_id bigint [not null]
+  title varchar(200) [not null]
+  content text [null]
+  created_at timestamp [default: `now()`]
+
+  indexes {
+    user_id [name: 'idx_posts_user_id']
+    (user_id, created_at) [name: 'idx_posts_user_created']
+  }
+}
+
+Ref: posts.user_id > users.id [delete: cascade, update: no action]
+```
+
+## DBML Features
+
+### Table Definitions
+```dbml
+Table table_name {
+  column_name type [attributes]
+}
+```
+
+### Column Attributes
+- `pk` - Primary key
+- `increment` - Auto-increment
+- `not null` - NOT NULL constraint
+- `null` - Nullable (explicit)
+- `unique` - Unique constraint
+- `default: value` - Default value
+- `note: 'text'` - Column note
+
+### Relationships
+```dbml
+Ref: table1.column > table2.column
+Ref: table1.column < table2.column
+Ref: table1.column - table2.column
+```
+
+Relationship types:
+- `>` - Many-to-one
+- `<` - One-to-many
+- `-` - One-to-one
+
+Relationship actions:
+```dbml
+Ref: posts.user_id > users.id [delete: cascade, update: restrict]
+```
+
+### Indexes
+```dbml
+indexes {
+  column_name
+  (column1, column2) [name: 'idx_name', unique]
+}
+```
+
+## Type Mapping
+
+| SQL Type | DBML Type |
+|----------|-----------|
+| bigint | bigint |
+| integer | int |
+| varchar(n) | varchar(n) |
+| text | text |
+| boolean | boolean |
+| timestamp | timestamp |
+| date | date |
+| json | json |
+| uuid | uuid |
+
+## Notes
+
+- DBML is designed for database visualization
+- Can be imported into dbdiagram.io
+- Human-readable format
+- Schema names can be included in table names
+- Comments and notes are preserved
+- Ideal for documentation and sharing designs

pkg/writers/dctx/README.md

@@ -0,0 +1,111 @@
+# DCTX Writer
+
+Generates Clarion database dictionary (DCTX) files from database schema information.
+
+## Overview
+
+The DCTX Writer converts RelSpec's internal database model representation into Clarion dictionary XML format, used by the Clarion development platform.
+
+## Features
+
+- Generates DCTX XML format
+- Creates file (table) definitions
+- Defines fields (columns) with Clarion types
+- Includes keys (indexes)
+- Handles relationships
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/dctx"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "database.dctx",
+    }
+
+    writer := dctx.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate DCTX from PostgreSQL database (for Clarion migration)
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output dctx \
+  --out-file app.dctx
+
+# Convert GORM models to DCTX
+relspec --input gorm --in-file models.go --output dctx --out-file legacy.dctx
+
+# Convert JSON schema to DCTX
+relspec --input json --in-file schema.json --output dctx --out-file database.dctx
+```
+
+## Type Mapping
+
+Converts standard SQL types to Clarion types:
+
+| SQL Type | Clarion Type | Notes |
+|----------|--------------|-------|
+| VARCHAR(n) | STRING(n) | Fixed-length string |
+| TEXT | STRING | Variable length |
+| INTEGER | LONG | 32-bit integer |
+| BIGINT | DECIMAL(20,0) | Large integer |
+| SMALLINT | SHORT | 16-bit integer |
+| NUMERIC(p,s) | DECIMAL(p,s) | Decimal number |
+| REAL, FLOAT | REAL | Floating point |
+| BOOLEAN | BYTE | 0/1 value |
+| DATE | DATE | Date field |
+| TIME | TIME | Time field |
+| TIMESTAMP | LONG | Unix timestamp |
+
+## DCTX Structure
+
+DCTX files are XML-based with this structure:
+
+```xml
+<?xml version="1.0"?>
+<dictionary>
+  <file name="USERS" driver="TOPSPEED">
+    <record>
+      <field name="ID" type="LONG" />
+      <field name="USERNAME" type="STRING" bytes="50" />
+      <field name="EMAIL" type="STRING" bytes="100" />
+    </record>
+    <key name="KEY_PRIMARY" primary="true">
+      <field name="ID" />
+    </key>
+  </file>
+</dictionary>
+```
+
+## Features
+
+- File definitions (equivalent to tables)
+- Field definitions with Clarion-specific types
+- Key definitions (primary and foreign)
+- Relationships between files
+- Driver specifications (TOPSPEED, SQL, etc.)
+
+## Notes
+
+- DCTX is specific to Clarion development
+- Useful for legacy system integration
+- Field names are typically uppercase in Clarion
+- Supports Clarion-specific attributes
+- Can be imported into Clarion IDE

pkg/writers/drawdb/README.md

@@ -0,0 +1,182 @@
+# DrawDB Writer
+
+Generates DrawDB-compatible JSON files from database schema information.
+
+## Overview
+
+The DrawDB Writer converts RelSpec's internal database model representation into JSON format compatible with DrawDB, a free online database design tool.
+
+## Features
+
+- Generates DrawDB JSON format
+- Creates table and field definitions
+- Defines relationships
+- Includes visual layout information
+- Preserves constraints and indexes
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/drawdb"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "diagram.json",
+    }
+
+    writer := drawdb.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate DrawDB diagram from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output drawdb \
+  --out-file diagram.json
+
+# Convert GORM models to DrawDB for visualization
+relspec --input gorm --in-file models.go --output drawdb --out-file design.json
+
+# Convert JSON schema to DrawDB
+relspec --input json --in-file schema.json --output drawdb --out-file diagram.json
+```
+
+## Generated JSON Example
+
+```json
+{
+  "version": "1.0",
+  "database": "PostgreSQL",
+  "tables": [
+    {
+      "id": "1",
+      "name": "users",
+      "x": 100,
+      "y": 100,
+      "fields": [
+        {
+          "id": "1",
+          "name": "id",
+          "type": "BIGINT",
+          "primary": true,
+          "autoIncrement": true,
+          "notNull": true
+        },
+        {
+          "id": "2",
+          "name": "username",
+          "type": "VARCHAR",
+          "size": 50,
+          "notNull": true,
+          "unique": true
+        },
+        {
+          "id": "3",
+          "name": "email",
+          "type": "VARCHAR",
+          "size": 100,
+          "notNull": true
+        }
+      ],
+      "indexes": [
+        {
+          "name": "idx_users_email",
+          "fields": ["email"]
+        }
+      ]
+    },
+    {
+      "id": "2",
+      "name": "posts",
+      "x": 400,
+      "y": 100,
+      "fields": [
+        {
+          "id": "1",
+          "name": "id",
+          "type": "BIGINT",
+          "primary": true
+        },
+        {
+          "id": "2",
+          "name": "user_id",
+          "type": "BIGINT",
+          "notNull": true
+        },
+        {
+          "id": "3",
+          "name": "title",
+          "type": "VARCHAR",
+          "size": 200,
+          "notNull": true
+        }
+      ]
+    }
+  ],
+  "relationships": [
+    {
+      "id": "1",
+      "source": "2",
+      "target": "1",
+      "sourceField": "user_id",
+      "targetField": "id",
+      "type": "many-to-one",
+      "onDelete": "CASCADE"
+    }
+  ]
+}
+```
+
+## DrawDB Features
+
+### Table Properties
+- `id` - Unique table identifier
+- `name` - Table name
+- `x`, `y` - Position in diagram
+- `fields` - Array of field definitions
+- `indexes` - Array of index definitions
+
+### Field Properties
+- `id` - Unique field identifier
+- `name` - Field name
+- `type` - Data type (BIGINT, VARCHAR, etc.)
+- `size` - Length for string types
+- `primary` - Primary key flag
+- `notNull` - NOT NULL constraint
+- `unique` - Unique constraint
+- `autoIncrement` - Auto-increment flag
+- `default` - Default value
+
+### Relationship Properties
+- `id` - Unique relationship identifier
+- `source` - Source table ID
+- `target` - Target table ID
+- `sourceField` - Foreign key field
+- `targetField` - Referenced field
+- `type` - Relationship type (one-to-one, one-to-many, many-to-one)
+- `onDelete` - Delete action
+- `onUpdate` - Update action
+
+## Notes
+
+- DrawDB is available at drawdb.vercel.app
+- Generated files can be imported for visual editing
+- Visual positions (x, y) are auto-generated
+- Ideal for creating ERD diagrams
+- Supports modern database features
+- Free and open-source tool

pkg/writers/drizzle/README.md

@@ -0,0 +1,120 @@
+# Drizzle Writer
+
+Generates TypeScript/JavaScript files with Drizzle ORM schema definitions from database schema information.
+
+## Overview
+
+The Drizzle Writer converts RelSpec's internal database model representation into TypeScript source code with Drizzle ORM schema definitions, including tables, columns, relationships, and constraints.
+
+## Features
+
+- Generates Drizzle-compatible TypeScript schema
+- Supports PostgreSQL and MySQL schemas
+- Creates table definitions with proper column types
+- Generates relationship definitions
+- Handles constraints and indexes
+- Outputs formatted TypeScript code
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/drizzle"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.ts",
+        Metadata: map[string]interface{}{
+            "database_type": "postgresql", // or "mysql"
+        },
+    }
+
+    writer := drizzle.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate Drizzle schema from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output drizzle \
+  --out-file schema.ts
+
+# Convert GORM models to Drizzle
+relspec --input gorm --in-file models.go --output drizzle --out-file schema.ts
+
+# Convert JSON schema to Drizzle
+relspec --input json --in-file schema.json --output drizzle --out-file db/schema.ts
+```
+
+## Generated Code Example
+
+```typescript
+import { pgTable, serial, varchar, text, timestamp, integer } from 'drizzle-orm/pg-core';
+import { relations } from 'drizzle-orm';
+
+export const users = pgTable('users', {
+  id: serial('id').primaryKey(),
+  username: varchar('username', { length: 50 }).notNull().unique(),
+  email: varchar('email', { length: 100 }).notNull(),
+  bio: text('bio'),
+  createdAt: timestamp('created_at').notNull().defaultNow(),
+});
+
+export const posts = pgTable('posts', {
+  id: serial('id').primaryKey(),
+  userId: integer('user_id').notNull().references(() => users.id, { onDelete: 'cascade' }),
+  title: varchar('title', { length: 200 }).notNull(),
+  content: text('content'),
+});
+
+export const usersRelations = relations(users, ({ many }) => ({
+  posts: many(posts),
+}));
+
+export const postsRelations = relations(posts, ({ one }) => ({
+  user: one(users, {
+    fields: [posts.userId],
+    references: [users.id],
+  }),
+}));
+```
+
+## Supported Column Types
+
+### PostgreSQL
+- `serial`, `bigserial` - Auto-increment integers
+- `integer`, `bigint`, `smallint` - Integer types
+- `varchar`, `text` - String types
+- `boolean` - Boolean
+- `timestamp`, `date`, `time` - Date/time types
+- `json`, `jsonb` - JSON types
+- `uuid` - UUID type
+
+### MySQL
+- `int`, `bigint`, `smallint` - Integer types
+- `varchar`, `text` - String types
+- `boolean` - Boolean
+- `datetime`, `timestamp` - Date/time types
+- `json` - JSON type
+
+## Notes
+
+- Table names and column names are preserved as-is
+- Relationships are generated as separate relation definitions
+- Constraint actions (CASCADE, etc.) are included in references
+- Schema names other than 'public' are supported
+- Output is formatted TypeScript code

pkg/writers/gorm/README.md

@@ -0,0 +1,176 @@
+# GORM Writer
+
+Generates Go source files with GORM model definitions from database schema information.
+
+## Overview
+
+The GORM Writer converts RelSpec's internal database model representation into Go source code with GORM struct definitions, complete with proper tags, relationships, and methods.
+
+## Features
+
+- Generates GORM-compatible Go structs
+- Creates proper `gorm` struct tags
+- Generates `TableName()` methods
+- Adds relationship fields (belongs-to, has-many)
+- Supports both single-file and multi-file output
+- Auto-generates helper methods (optional)
+- Maps SQL types to Go types
+- Handles nullable fields with custom sql_types
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/gorm"
+)
+
+func main() {
+    // Assume db is a *models.Database from a reader
+    options := &writers.WriterOptions{
+        OutputPath:  "models.go",
+        PackageName: "models",
+    }
+
+    writer := gorm.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate GORM models from PostgreSQL database (single file)
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output gorm \
+  --out-file models.go \
+  --package models
+
+# Generate GORM models with multi-file output (one file per table)
+relspec --input json \
+  --in-file schema.json \
+  --output gorm \
+  --out-file models/ \
+  --package models
+
+# Convert DBML to GORM models
+relspec --input dbml --in-file schema.dbml --output gorm --out-file models.go
+```
+
+## Output Modes
+
+### Single File Mode
+
+Generates all models in one file:
+
+```bash
+relspec --input pgsql --conn "..." --output gorm --out-file models.go
+```
+
+### Multi-File Mode
+
+Generates one file per table (auto-detected when output is a directory):
+
+```bash
+relspec --input pgsql --conn "..." --output gorm --out-file models/
+```
+
+Files are named: `sql_{schema}_{table}.go`
+
+## Generated Code Example
+
+```go
+package models
+
+import (
+    "time"
+    sql_types "git.warky.dev/wdevs/sql_types"
+)
+
+type ModelUser struct {
+    ID        int64                `gorm:"column:id;type:bigint;primaryKey;autoIncrement" json:"id"`
+    Username  string               `gorm:"column:username;type:varchar(50);not null;uniqueIndex" json:"username"`
+    Email     string               `gorm:"column:email;type:varchar(100);not null" json:"email"`
+    CreatedAt time.Time            `gorm:"column:created_at;type:timestamp;not null;default:now()" json:"created_at"`
+
+    // Relationships
+    Pos []*ModelPost `gorm:"foreignKey:UserID;references:ID;constraint:OnDelete:CASCADE" json:"pos,omitempty"`
+}
+
+func (ModelUser) TableName() string {
+    return "public.users"
+}
+
+type ModelPost struct {
+    ID        int64           `gorm:"column:id;type:bigint;primaryKey" json:"id"`
+    UserID    int64           `gorm:"column:user_id;type:bigint;not null" json:"user_id"`
+    Title     string          `gorm:"column:title;type:varchar(200);not null" json:"title"`
+    Content   sql_types.SqlString `gorm:"column:content;type:text" json:"content,omitempty"`
+
+    // Belongs to
+    Use *ModelUser `gorm:"foreignKey:UserID;references:ID" json:"use,omitempty"`
+}
+
+func (ModelPost) TableName() string {
+    return "public.posts"
+}
+```
+
+## Writer Options
+
+### Metadata Options
+
+Configure the writer behavior using metadata in `WriterOptions`:
+
+```go
+options := &writers.WriterOptions{
+    OutputPath:  "models.go",
+    PackageName: "models",
+    Metadata: map[string]interface{}{
+        "multi_file":      true,  // Enable multi-file mode
+        "populate_refs":   true,  // Populate RefDatabase/RefSchema
+        "generate_get_id_str": true, // Generate GetIDStr() methods
+    },
+}
+```
+
+## Type Mapping
+
+| SQL Type | Go Type | Notes |
+|----------|---------|-------|
+| bigint, int8 | int64 | - |
+| integer, int, int4 | int | - |
+| smallint, int2 | int16 | - |
+| varchar, text | string | Not nullable |
+| varchar, text (nullable) | sql_types.SqlString | Nullable |
+| boolean, bool | bool | - |
+| timestamp, timestamptz | time.Time | - |
+| numeric, decimal | float64 | - |
+| uuid | string | - |
+| json, jsonb | string | - |
+
+## Relationship Generation
+
+The writer automatically generates relationship fields:
+
+- **Belongs-to**: Generated for tables with foreign keys
+- **Has-many**: Generated for tables referenced by foreign keys
+- Relationship field names use 3-letter prefixes
+- Includes proper `gorm` tags with `foreignKey` and `references`
+
+## Notes
+
+- Model names are prefixed with "Model" (e.g., `ModelUser`)
+- Nullable columns use `sql_types.SqlString`, `sql_types.SqlInt64`, etc.
+- Generated code is auto-formatted with `go fmt`
+- JSON tags are automatically added
+- Supports schema-qualified table names in `TableName()` method

pkg/writers/json/README.md

@@ -0,0 +1,277 @@
+# JSON Writer
+
+Generates database schema definitions in JSON format.
+
+## Overview
+
+The JSON Writer converts RelSpec's internal database model representation into JSON format, providing a complete, structured representation of the database schema.
+
+## Features
+
+- Generates RelSpec's canonical JSON schema format
+- Complete schema representation including:
+  - Databases and schemas
+  - Tables, columns, and data types
+  - Constraints (PK, FK, unique, check)
+  - Indexes
+  - Relationships
+  - Views and sequences
+- Pretty-printed, human-readable output
+- Suitable for version control
+- Ideal interchange format
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/json"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.json",
+    }
+
+    writer := json.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Export PostgreSQL database to JSON
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output json \
+  --out-file schema.json
+
+# Convert GORM models to JSON
+relspec --input gorm --in-file models.go --output json --out-file schema.json
+
+# Convert DBML to JSON
+relspec --input dbml --in-file diagram.dbml --output json --out-file schema.json
+```
+
+## Generated JSON Example
+
+```json
+{
+  "name": "myapp",
+  "description": "",
+  "database_type": "postgresql",
+  "database_version": "",
+  "source_format": "pgsql",
+  "schemas": [
+    {
+      "name": "public",
+      "description": "",
+      "tables": [
+        {
+          "name": "users",
+          "schema": "public",
+          "description": "",
+          "columns": {
+            "id": {
+              "name": "id",
+              "table": "users",
+              "schema": "public",
+              "type": "bigint",
+              "length": 0,
+              "precision": 0,
+              "scale": 0,
+              "not_null": true,
+              "is_primary_key": true,
+              "auto_increment": true,
+              "default": "",
+              "sequence": 1
+            },
+            "username": {
+              "name": "username",
+              "table": "users",
+              "schema": "public",
+              "type": "varchar",
+              "length": 50,
+              "not_null": true,
+              "is_primary_key": false,
+              "auto_increment": false,
+              "sequence": 2
+            },
+            "email": {
+              "name": "email",
+              "table": "users",
+              "schema": "public",
+              "type": "varchar",
+              "length": 100,
+              "not_null": true,
+              "sequence": 3
+            }
+          },
+          "constraints": {
+            "pk_users": {
+              "name": "pk_users",
+              "type": "PRIMARY KEY",
+              "table": "users",
+              "schema": "public",
+              "columns": ["id"]
+            },
+            "uq_users_username": {
+              "name": "uq_users_username",
+              "type": "UNIQUE",
+              "table": "users",
+              "schema": "public",
+              "columns": ["username"]
+            }
+          },
+          "indexes": {
+            "idx_users_email": {
+              "name": "idx_users_email",
+              "table": "users",
+              "schema": "public",
+              "columns": ["email"],
+              "unique": false,
+              "type": "btree"
+            }
+          },
+          "relationships": {}
+        },
+        {
+          "name": "posts",
+          "schema": "public",
+          "columns": {
+            "id": {
+              "name": "id",
+              "type": "bigint",
+              "not_null": true,
+              "is_primary_key": true,
+              "sequence": 1
+            },
+            "user_id": {
+              "name": "user_id",
+              "type": "bigint",
+              "not_null": true,
+              "sequence": 2
+            },
+            "title": {
+              "name": "title",
+              "type": "varchar",
+              "length": 200,
+              "not_null": true,
+              "sequence": 3
+            },
+            "content": {
+              "name": "content",
+              "type": "text",
+              "not_null": false,
+              "sequence": 4
+            }
+          },
+          "constraints": {
+            "fk_posts_user_id": {
+              "name": "fk_posts_user_id",
+              "type": "FOREIGN KEY",
+              "table": "posts",
+              "schema": "public",
+              "columns": ["user_id"],
+              "referenced_table": "users",
+              "referenced_schema": "public",
+              "referenced_columns": ["id"],
+              "on_delete": "CASCADE",
+              "on_update": "NO ACTION"
+            }
+          },
+          "indexes": {
+            "idx_posts_user_id": {
+              "name": "idx_posts_user_id",
+              "columns": ["user_id"],
+              "unique": false,
+              "type": "btree"
+            }
+          }
+        }
+      ],
+      "views": [],
+      "sequences": []
+    }
+  ]
+}
+```
+
+## Schema Structure
+
+The JSON format includes:
+
+### Database Level
+- `name` - Database name
+- `description` - Database description
+- `database_type` - Database system type
+- `database_version` - Version information
+- `source_format` - Original source format
+- `schemas` - Array of schema objects
+
+### Schema Level
+- `name` - Schema name
+- `description` - Schema description
+- `tables` - Array of table objects
+- `views` - Array of view objects
+- `sequences` - Array of sequence objects
+
+### Table Level
+- `name` - Table name
+- `schema` - Schema name
+- `description` - Table description
+- `columns` - Map of column objects
+- `constraints` - Map of constraint objects
+- `indexes` - Map of index objects
+- `relationships` - Map of relationship objects
+
+### Column Level
+- `name` - Column name
+- `type` - Data type
+- `length` - Type length
+- `precision`, `scale` - Numeric precision
+- `not_null` - NOT NULL flag
+- `is_primary_key` - Primary key flag
+- `auto_increment` - Auto-increment flag
+- `default` - Default value
+- `sequence` - Column order
+
+### Constraint Level
+- `name` - Constraint name
+- `type` - Constraint type (PRIMARY KEY, FOREIGN KEY, UNIQUE, CHECK)
+- `columns` - Constrained columns
+- `referenced_table`, `referenced_schema` - FK references
+- `referenced_columns` - Referenced columns
+- `on_delete`, `on_update` - FK actions
+
+### Index Level
+- `name` - Index name
+- `columns` - Indexed columns
+- `unique` - Unique flag
+- `type` - Index type
+
+## Use Cases
+
+- **Version Control** - Track schema changes in git
+- **Documentation** - Human-readable schema documentation
+- **Interchange** - Standard format for tool integration
+- **Backup** - Schema backup without database access
+- **Testing** - Test data for schema validation
+- **API** - Schema information for APIs
+
+## Notes
+
+- Output is pretty-printed with 2-space indentation
+- Preserves all schema metadata
+- Can be round-tripped (read and write) without loss
+- Schema-agnostic format
+- Ideal for automation and tooling

pkg/writers/pgsql/README.md

@@ -0,0 +1,195 @@
+# PostgreSQL Writer
+
+Generates PostgreSQL DDL (Data Definition Language) SQL scripts from database schema information.
+
+## Overview
+
+The PostgreSQL Writer converts RelSpec's internal database model representation into PostgreSQL-compatible SQL DDL scripts, including CREATE TABLE statements, constraints, indexes, views, and sequences.
+
+## Features
+
+- Generates complete PostgreSQL DDL
+- Creates schemas, tables, columns
+- Defines constraints (PK, FK, unique, check)
+- Creates indexes
+- Generates views and sequences
+- Supports migration scripts
+- Includes audit triggers (optional)
+- Handles PostgreSQL-specific data types
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/pgsql"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.sql",
+    }
+
+    writer := pgsql.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate PostgreSQL DDL from JSON schema
+relspec --input json \
+  --in-file schema.json \
+  --output pgsql \
+  --out-file schema.sql
+
+# Convert GORM models to PostgreSQL DDL
+relspec --input gorm \
+  --in-file models.go \
+  --output pgsql \
+  --out-file create_tables.sql
+
+# Export live database schema to SQL
+relspec --input pgsql \
+  --conn "postgres://localhost/source_db" \
+  --output pgsql \
+  --out-file backup_schema.sql
+```
+
+## Generated SQL Example
+
+```sql
+-- Schema: public
+
+CREATE SCHEMA IF NOT EXISTS public;
+
+-- Table: public.users
+
+CREATE TABLE IF NOT EXISTS public.users (
+    id BIGSERIAL PRIMARY KEY,
+    username VARCHAR(50) NOT NULL,
+    email VARCHAR(100) NOT NULL,
+    bio TEXT,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+-- Constraints for public.users
+
+ALTER TABLE public.users
+    ADD CONSTRAINT uq_users_username UNIQUE (username);
+
+-- Indexes for public.users
+
+CREATE INDEX idx_users_email ON public.users (email);
+
+-- Table: public.posts
+
+CREATE TABLE IF NOT EXISTS public.posts (
+    id BIGSERIAL PRIMARY KEY,
+    user_id BIGINT NOT NULL,
+    title VARCHAR(200) NOT NULL,
+    content TEXT,
+    created_at TIMESTAMP DEFAULT NOW()
+);
+
+-- Foreign Keys for public.posts
+
+ALTER TABLE public.posts
+    ADD CONSTRAINT fk_posts_user_id
+    FOREIGN KEY (user_id)
+    REFERENCES public.users (id)
+    ON DELETE CASCADE
+    ON UPDATE NO ACTION;
+
+-- Indexes for public.posts
+
+CREATE INDEX idx_posts_user_id ON public.posts (user_id);
+```
+
+## Writer Options
+
+### Metadata Options
+
+```go
+options := &writers.WriterOptions{
+    OutputPath: "schema.sql",
+    Metadata: map[string]interface{}{
+        "include_drop":    true,  // Include DROP statements
+        "include_audit":   true,  // Include audit triggers
+        "if_not_exists":   true,  // Use IF NOT EXISTS
+        "migration_mode":  false, // Generate migration script
+    },
+}
+```
+
+## Features
+
+### Full DDL Generation
+
+Generates complete database structure:
+- CREATE SCHEMA statements
+- CREATE TABLE with all columns and types
+- PRIMARY KEY constraints
+- FOREIGN KEY constraints with actions
+- UNIQUE constraints
+- CHECK constraints
+- CREATE INDEX statements
+- CREATE VIEW statements
+- CREATE SEQUENCE statements
+
+### Migration Mode
+
+When `migration_mode` is enabled, generates migration scripts with:
+- Version tracking
+- Up/down migrations
+- Transactional DDL
+- Rollback support
+
+### Audit Triggers
+
+When `include_audit` is enabled, adds:
+- Created/updated timestamp triggers
+- Audit logging functionality
+- Change tracking
+
+## PostgreSQL-Specific Features
+
+- Serial types (SERIAL, BIGSERIAL)
+- Advanced types (UUID, JSONB, ARRAY)
+- Schema-qualified names
+- Constraint actions (CASCADE, RESTRICT, SET NULL)
+- Partial indexes
+- Function-based indexes
+- Check constraints with expressions
+
+## Data Types
+
+Supports all PostgreSQL data types:
+- Integer types: SMALLINT, INTEGER, BIGINT, SERIAL, BIGSERIAL
+- Numeric types: NUMERIC, DECIMAL, REAL, DOUBLE PRECISION
+- String types: VARCHAR, CHAR, TEXT
+- Date/Time: DATE, TIME, TIMESTAMP, TIMESTAMPTZ, INTERVAL
+- Boolean: BOOLEAN
+- Binary: BYTEA
+- JSON: JSON, JSONB
+- UUID: UUID
+- Network: INET, CIDR, MACADDR
+- Special: ARRAY, HSTORE
+
+## Notes
+
+- Generated SQL is formatted and readable
+- Comments are preserved from source schema
+- Schema names are fully qualified
+- Default values are properly quoted
+- Constraint names follow PostgreSQL conventions
+- Compatible with PostgreSQL 12+

pkg/writers/prisma/README.md

@@ -0,0 +1,135 @@
+# Prisma Writer
+
+Generates Prisma schema files from database schema information.
+
+## Overview
+
+The Prisma Writer converts RelSpec's internal database model representation into Prisma schema language (`.prisma` files), complete with models, fields, relationships, and attributes.
+
+## Features
+
+- Generates Prisma schema syntax
+- Creates model definitions with proper field types
+- Adds Prisma attributes (@id, @unique, @default, etc.)
+- Generates relationship fields
+- Includes datasource and generator configurations
+- Maps table/column names with @map and @@map
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/prisma"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.prisma",
+        Metadata: map[string]interface{}{
+            "datasource_provider": "postgresql",
+        },
+    }
+
+    writer := prisma.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate Prisma schema from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output prisma \
+  --out-file schema.prisma
+
+# Convert GORM models to Prisma
+relspec --input gorm --in-file models.go --output prisma --out-file schema.prisma
+
+# Convert JSON to Prisma schema
+relspec --input json --in-file database.json --output prisma --out-file prisma/schema.prisma
+```
+
+## Generated Code Example
+
+```prisma
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+model User {
+  id        Int      @id @default(autoincrement())
+  username  String   @unique @db.VarChar(50)
+  email     String   @db.VarChar(100)
+  bio       String?  @db.Text
+  createdAt DateTime @default(now()) @map("created_at")
+
+  posts Post[]
+
+  @@map("users")
+}
+
+model Post {
+  id      Int     @id @default(autoincrement())
+  userId  Int     @map("user_id")
+  title   String  @db.VarChar(200)
+  content String? @db.Text
+
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@map("posts")
+}
+```
+
+## Supported Prisma Attributes
+
+### Field Attributes
+- `@id` - Primary key
+- `@unique` - Unique constraint
+- `@default()` - Default value
+- `@map()` - Column name mapping
+- `@db.*` - Database-specific types
+- `@relation()` - Relationship definition
+
+### Model Attributes
+- `@@map()` - Table name mapping
+- `@@unique()` - Composite unique constraints
+- `@@index()` - Index definitions
+- `@@id()` - Composite primary keys
+
+## Type Mapping
+
+| SQL Type | Prisma Type | Database Type |
+|----------|-------------|---------------|
+| bigint | Int | @db.BigInt |
+| integer | Int | - |
+| varchar(n) | String | @db.VarChar(n) |
+| text | String | @db.Text |
+| boolean | Boolean | - |
+| timestamp | DateTime | @db.Timestamp |
+| uuid | String | @db.Uuid |
+| json | Json | - |
+
+## Notes
+
+- Model names are PascalCase (e.g., `User`, `Post`)
+- Field names are camelCase with `@map` for snake_case columns
+- Table names use `@@map` when different from model name
+- Nullable fields are marked with `?`
+- Relationship fields are automatically generated
+- Datasource provider defaults to `postgresql`

pkg/writers/typeorm/README.md

@@ -0,0 +1,169 @@
+# TypeORM Writer
+
+Generates TypeScript files with TypeORM entity definitions from database schema information.
+
+## Overview
+
+The TypeORM Writer converts RelSpec's internal database model representation into TypeScript source code with TypeORM entity classes, including proper decorators, relationships, and column configurations.
+
+## Features
+
+- Generates TypeORM-compatible TypeScript entities
+- Creates proper decorator usage (@Entity, @Column, etc.)
+- Adds relationship decorators (@OneToMany, @ManyToOne, @JoinColumn)
+- Handles column types and options
+- Supports constraints and indexes
+- Outputs formatted TypeScript code
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/typeorm"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "entities/",
+    }
+
+    writer := typeorm.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Generate TypeORM entities from PostgreSQL database
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output typeorm \
+  --out-file entities/
+
+# Convert GORM models to TypeORM
+relspec --input gorm --in-file models.go --output typeorm --out-file src/entities/
+
+# Convert JSON to TypeORM entities
+relspec --input json --in-file schema.json --output typeorm --out-file entities/
+```
+
+## Generated Code Example
+
+```typescript
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  OneToMany,
+  ManyToOne,
+  JoinColumn,
+  Index,
+} from 'typeorm';
+import { Post } from './Post';
+
+@Entity('users')
+export class User {
+  @PrimaryGeneratedColumn('increment')
+  id: number;
+
+  @Column({ type: 'varchar', length: 50, unique: true })
+  @Index()
+  username: string;
+
+  @Column({ type: 'varchar', length: 100 })
+  email: string;
+
+  @Column({ type: 'text', nullable: true })
+  bio: string | null;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @OneToMany(() => Post, (post) => post.user)
+  posts: Post[];
+}
+
+@Entity('posts')
+export class Post {
+  @PrimaryGeneratedColumn('increment')
+  id: number;
+
+  @Column({ name: 'user_id' })
+  userId: number;
+
+  @Column({ type: 'varchar', length: 200 })
+  title: string;
+
+  @Column({ type: 'text', nullable: true })
+  content: string | null;
+
+  @ManyToOne(() => User, (user) => user.posts, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'user_id' })
+  user: User;
+}
+```
+
+## Supported TypeORM Decorators
+
+### Entity Decorators
+- `@Entity()` - Define entity/table
+- `@PrimaryGeneratedColumn()` - Auto-increment primary key
+- `@PrimaryColumn()` - Primary key
+- `@Column()` - Column definition
+- `@CreateDateColumn()` - Auto-set creation timestamp
+- `@UpdateDateColumn()` - Auto-update timestamp
+
+### Relationship Decorators
+- `@OneToMany()` - One-to-many relationship
+- `@ManyToOne()` - Many-to-one relationship
+- `@JoinColumn()` - Foreign key column specification
+
+### Constraint Decorators
+- `@Index()` - Create index
+- `@Unique()` - Unique constraint
+
+## Column Options
+
+```typescript
+@Column({
+  type: 'varchar',      // Column type
+  length: 255,          // Length for varchar/char
+  nullable: true,       // Allow NULL
+  unique: true,         // Unique constraint
+  default: 'value',     // Default value
+  name: 'column_name',  // Database column name
+})
+```
+
+## Type Mapping
+
+| SQL Type | TypeScript Type | TypeORM Type |
+|----------|-----------------|--------------|
+| bigint | number | 'bigint' |
+| integer | number | 'int' |
+| varchar | string | 'varchar' |
+| text | string | 'text' |
+| boolean | boolean | 'boolean' |
+| timestamp | Date | 'timestamp' |
+| json | object | 'json' |
+| uuid | string | 'uuid' |
+
+## Notes
+
+- Entity class names are PascalCase
+- One file per entity (named after the entity)
+- Relationship imports are auto-generated
+- Nullable columns use TypeScript union with `null`
+- Foreign key actions (CASCADE, etc.) are included
+- Schema names can be specified in `@Entity()` decorator

pkg/writers/yaml/README.md

@@ -0,0 +1,212 @@
+# YAML Writer
+
+Generates database schema definitions in YAML format.
+
+## Overview
+
+The YAML Writer converts RelSpec's internal database model representation into YAML format, providing a human-readable, structured representation of the database schema.
+
+## Features
+
+- Generates RelSpec's canonical YAML schema format
+- Human-readable alternative to JSON
+- Complete schema representation including:
+  - Databases and schemas
+  - Tables, columns, and data types
+  - Constraints (PK, FK, unique, check)
+  - Indexes
+  - Relationships
+  - Views and sequences
+- Supports comments
+- Ideal for manual editing and configuration
+
+## Usage
+
+### Basic Example
+
+```go
+package main
+
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/models"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/yaml"
+)
+
+func main() {
+    options := &writers.WriterOptions{
+        OutputPath: "schema.yaml",
+    }
+
+    writer := yaml.NewWriter(options)
+    err := writer.WriteDatabase(db)
+    if err != nil {
+        panic(err)
+    }
+}
+```
+
+### CLI Examples
+
+```bash
+# Export PostgreSQL database to YAML
+relspec --input pgsql \
+  --conn "postgres://localhost/mydb" \
+  --output yaml \
+  --out-file schema.yaml
+
+# Convert GORM models to YAML
+relspec --input gorm --in-file models.go --output yaml --out-file schema.yaml
+
+# Convert JSON to YAML
+relspec --input json --in-file schema.json --output yaml --out-file schema.yaml
+```
+
+## Generated YAML Example
+
+```yaml
+name: myapp
+database_type: postgresql
+source_format: pgsql
+schemas:
+  - name: public
+    tables:
+      - name: users
+        schema: public
+        columns:
+          id:
+            name: id
+            table: users
+            schema: public
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            auto_increment: true
+            sequence: 1
+          username:
+            name: username
+            table: users
+            schema: public
+            type: varchar
+            length: 50
+            not_null: true
+            sequence: 2
+          email:
+            name: email
+            table: users
+            schema: public
+            type: varchar
+            length: 100
+            not_null: true
+            sequence: 3
+        constraints:
+          pk_users:
+            name: pk_users
+            type: PRIMARY KEY
+            table: users
+            schema: public
+            columns:
+              - id
+          uq_users_username:
+            name: uq_users_username
+            type: UNIQUE
+            table: users
+            schema: public
+            columns:
+              - username
+        indexes:
+          idx_users_email:
+            name: idx_users_email
+            table: users
+            schema: public
+            columns:
+              - email
+            unique: false
+            type: btree
+
+      - name: posts
+        schema: public
+        columns:
+          id:
+            name: id
+            type: bigint
+            not_null: true
+            is_primary_key: true
+            sequence: 1
+          user_id:
+            name: user_id
+            type: bigint
+            not_null: true
+            sequence: 2
+          title:
+            name: title
+            type: varchar
+            length: 200
+            not_null: true
+            sequence: 3
+          content:
+            name: content
+            type: text
+            not_null: false
+            sequence: 4
+        constraints:
+          fk_posts_user_id:
+            name: fk_posts_user_id
+            type: FOREIGN KEY
+            table: posts
+            schema: public
+            columns:
+              - user_id
+            referenced_table: users
+            referenced_schema: public
+            referenced_columns:
+              - id
+            on_delete: CASCADE
+            on_update: NO ACTION
+        indexes:
+          idx_posts_user_id:
+            name: idx_posts_user_id
+            columns:
+              - user_id
+            unique: false
+            type: btree
+    views: []
+    sequences: []
+```
+
+## Schema Structure
+
+The YAML format mirrors the JSON structure with human-readable syntax:
+
+- Database level: `name`, `database_type`, `source_format`, `schemas`
+- Schema level: `name`, `tables`, `views`, `sequences`
+- Table level: `name`, `schema`, `columns`, `constraints`, `indexes`
+- Column level: `name`, `type`, `length`, `not_null`, etc.
+- Constraint level: `name`, `type`, `columns`, foreign key details
+- Index level: `name`, `columns`, `unique`, `type`
+
+## Advantages Over JSON
+
+- More human-readable
+- Easier to edit manually
+- Supports comments
+- Less verbose (no braces/brackets)
+- Better for configuration files
+- Natural indentation
+
+## Use Cases
+
+- **Configuration** - Schema as configuration
+- **Documentation** - Human-readable schema docs
+- **Version Control** - Easier to read diffs
+- **Manual Editing** - Easier to modify by hand
+- **Code Generation** - Template-friendly format
+
+## Notes
+
+- Output is properly indented (2 spaces)
+- Preserves all schema metadata
+- Can be round-tripped with YAML reader
+- Compatible with YAML 1.2
+- More readable than JSON for large schemas
+- Ideal for documentation and manual workflows