sqldef

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What sqldef is

sqldef is a free, open-source command-line tool for comparing SQL schemas and managing relational database migrations with regular SQL DDL. You define the desired database structure in SQL, and sqldef compares it with the current schema before generating and applying the required changes. Supported databases are MySQL, MariaDB, TiDB, PostgreSQL, SQL Server, and SQLite3. Operations are designed to be idempotent, so repeating them is considered safe. A dry-run option previews migrations without execution, while offline mode compares SQL files without connecting to a database for validation, CI/CD, or migration-script generation. The @renamed annotation identifies renamed tables, columns, indexes, and ENUM values. Distribution includes pre-built single-binary executables and Docker images, and a GitHub Action can preview schema changes. The website also offers a WebAssembly browser demo. Source files use the MIT License, except the parser, which uses Apache License 2.0. Debian packages are unavailable for Linux.

Who it suits

sqldef suits developers and database teams managing schema changes from SQL files, including offline and CI/CD workflows. It supports self-hosted use across Linux, macOS, Windows, and web-based demonstration.

What it does well

Supports six listed database systems
Idempotent migrations can run repeatedly
Dry-run previews changes safely
Offline schema comparison needs no database
Provides binaries, Docker images, and GitHub Action

What to know first

Debian packages are unavailable
Command-line workflow requires SQL definitions
Parser uses a separate Apache 2.0 license

Verdict

sqldef offers a SQL-first workflow for schema diffing and migration generation across several databases. Its preview, offline, and automation options help teams review changes before applying them.

Facts from sqldef's own pages

Audience: The README describes a workflow for database schema changes that uses a single SQL file containing the complete schema. · github.com, 4 Oct 2026
Browser demo: The online demo uses a WebAssembly build to diff two SQL schemas and generate DDLs. · sqldef.github.io, 4 Oct 2026
Distribution: The project provides pre-built single-binary executables and Docker images. · github.com, 4 Oct 2026
Idempotency: The README says sqldef operations are idempotent and safe to run multiple times. · github.com, 4 Oct 2026
Idempotent operations: The project says its operations are safe to run multiple times. · github.com, 4 Oct 2026
Integration: A GitHub Action is available to preview database schema changes. · github.com, 4 Oct 2026
Integrations: The README links to a GitHub Action that previews database schema changes. · github.com, 4 Oct 2026
License: The sqldef source files are distributed under the MIT License, while the parser is distributed under Apache License 2.0. · github.com, 4 Oct 2026
Linux limitation: The project says Debian packages are not currently available and recommends pre-built binaries or Docker images instead. · github.com, 4 Oct 2026
Linux package limitation: The README says Debian packages are not currently available and directs Linux users to pre-built binaries or Docker images. · github.com, 4 Oct 2026
Migration preview: The --dry-run option shows migrations without executing them. · github.com, 4 Oct 2026
Offline mode: It can compare two SQL files without connecting to a database, including for CI/CD, schema validation, and migration script generation. · github.com, 4 Oct 2026
Online demo: The official site says its online demo uses a WebAssembly build of sqldef to diff schemas and generate DDLs. · sqldef.github.io, 4 Oct 2026
Platforms: The releases page lists downloadable binaries for Windows, macOS (Darwin), and Linux. · github.com, 4 Oct 2026
Preview and offline modes: sqldef can preview migrations without executing them and compare SQL files without connecting to a database. · github.com, 4 Oct 2026
Purpose: sqldef is a CLI tool for diffing SQL schemas and managing RDBMS migrations with regular SQL DDLs. · sqldef.github.io, 4 Oct 2026
Rename support: The README says the @renamed annotation supports renaming tables, columns, indexes, and ENUM values. · github.com, 4 Oct 2026
Schema workflow: Users define a desired schema in SQL, and sqldef generates and applies migrations to bring the database to that state. · github.com, 4 Oct 2026
Security and licensing: The README states that sqldef source files are distributed under the MIT License, except the parser, which is under Apache License 2.0. · github.com, 4 Oct 2026
Support: The project invites feature requests through pull requests or GitHub Discussions. · github.com, 4 Oct 2026
Supported databases: The site lists MySQL, MariaDB, TiDB, PostgreSQL, SQL Server, and SQLite3 as supported databases. · sqldef.github.io, 4 Oct 2026
Workflow: It compares a desired schema with the current schema and generates and applies DDLs to update the database. · github.com, 4 Oct 2026

Where sqldef stands on Freedom251

Database Migration Tools#31 of 32