RelSpec

Bidirectional database schema conversion, validation, and templating tool.

Install

go install -v git.warky.dev/wdevs/relspecgo/cmd/relspec@latest

Supported Formats

Direction	Formats
Readers	bun dbml dctx drawdb drizzle gorm graphql json mssql pgsql prisma sqldir sqlite typeorm yaml
Writers	bun dbml dctx drawdb drizzle gorm graphql json mssql pgsql prisma sqlexec sqlite template typeorm yaml

Commands

convert — Schema conversion

# PostgreSQL → GORM models
relspec convert --from pgsql --from-conn "postgres://user:pass@localhost/mydb" \
                --to gorm --to-path models/ --package models

# DBML → PostgreSQL DDL
relspec convert --from dbml --from-path schema.dbml --to pgsql --to-path schema.sql

# PostgreSQL → SQLite (auto flattens schemas)
relspec convert --from pgsql --from-conn "postgres://..." --to sqlite --to-path schema.sql

# Multiple input files merged
relspec convert --from json --from-list "a.json,b.json" --to yaml --to-path merged.yaml

PostgreSQL connections opened by relspec set application_name by default to relspecgo/<version> (with component suffixes internally, e.g. readers/writers). If you need a custom value, provide application_name explicitly in the connection string query parameters.

merge — Additive schema merge (never modifies existing items)

# Merge two JSON schemas
relspec merge --target json --target-path base.json \
              --source json --source-path additions.json \
              --output json --output-path merged.json

# Merge PostgreSQL into JSON, skipping tables
relspec merge --target json --target-path current.json \
              --source pgsql --source-conn "postgres://user:pass@localhost/db" \
              --output json --output-path updated.json \
              --skip-tables "audit_log,temp_tables"

Skip flags: --skip-relations --skip-views --skip-domains --skip-enums --skip-sequences

inspect — Schema validation / linting

# Validate PostgreSQL database
relspec inspect --from pgsql --from-conn "postgres://user:pass@localhost/mydb"

# Validate DBML with custom rules
relspec inspect --from dbml --from-path schema.dbml --rules .relspec-rules.yaml

# JSON report output
relspec inspect --from json --from-path db.json --output-format json --output report.json

# Filter to specific schema
relspec inspect --from pgsql --from-conn "..." --schema public

Rules: naming conventions, PK/FK standards, missing indexes, reserved keywords, circular dependencies.

diff — Schema comparison

relspec diff --from pgsql --from-conn "postgres://localhost/db1" \
             --to pgsql --to-conn "postgres://localhost/db2"

templ — Custom template rendering

# Render database schema to Markdown docs
relspec templ --from pgsql --from-conn "postgres://user:pass@localhost/db" \
              --template docs.tmpl --output schema-docs.md

# One TypeScript file per table
relspec templ --from dbml --from-path schema.dbml \
              --template ts-model.tmpl --mode table \
              --output ./models/ --filename-pattern "{{.Name | toCamelCase}}.ts"

Modes: database (default) · schema · table · script

Template functions: string utils (toCamelCase, toSnakeCase, pluralize, …), type converters (sqlToGo, sqlToTypeScript, …), filters, loop helpers, safe access.

edit — Interactive TUI editor

# Edit DBML schema interactively
relspec edit --from dbml --from-path schema.dbml --to dbml --to-path schema.dbml

# Edit live PostgreSQL database
relspec edit --from pgsql --from-conn "postgres://user:pass@localhost/mydb" \
             --to pgsql --to-conn "postgres://user:pass@localhost/mydb"

Development

Prerequisites: Go 1.24.0+

make build     # → build/relspec
make test      # race detection + coverage
make lint      # requires golangci-lint
make coverage  # → coverage.html
make install   # → $GOPATH/bin

Project Structure

cmd/relspec/          CLI commands
pkg/readers/          Input format readers
pkg/writers/          Output format writers
pkg/inspector/        Schema validation
pkg/diff/             Schema comparison
pkg/merge/            Schema merging
pkg/models/           Internal data models
pkg/transform/        Transformation logic
pkg/pgsql/            PostgreSQL utilities
pkg/sqltypes/         Nullable SQL types for generated/hand-written models (see below)

Nullable Types (pkg/sqltypes)

The bun and gorm writers can generate model structs using pkg/sqltypes — nullable types (SqlString, SqlInt32, SqlTimeStamp, SqlStringArray, …) that implement database/sql.Scanner, driver.Valuer, and JSON/YAML/XML marshalling in one type, selected via --types sqltypes. See the pkg/sqltypes README for the full type reference, or the bun / gorm writer docs for the --types flag (sqltypes, stdlib, or baselib). PostgreSQL array columns are the one exception: the bun writer always generates native Go slices ([]string, []int32, …) with an explicit array bun tag, regardless of --types — see bun's --array-nullable flag for nullable-array handling. The SqlXxxArray wrapper types remain available in pkg/sqltypes and are still used by the gorm writer.

Contributing

1. Register or sign in with GitHub at git.warky.dev
2. Clone the repository: git clone https://git.warky.dev/wdevs/relspecgo.git
3. Create a feature branch: git checkout -b feature/your-feature-name
4. Commit your changes and push the branch
5. Open a pull request with a description of the new feature or fix

For questions or discussion, join the Discord: discord.gg/74rcTujp25 — warkyhein

Links

• Todo
• AI Use Policy
• License — Apache 2.0 · Copyright 2025 Warky Devs