sqldef

sqldef is a command-line tool for teams that manage relational database schemas in SQL. It suits developers who want one declarative schema file to drive changes across multiple database engines, rather than maintaining migration steps by hand. Its breadth is useful, but the CLI workflow favors people comfortable working in SQL and command-line environments.

Overview

Keep a SQL file describing the complete schema you want, and sqldef compares it with the database to produce and apply the necessary DDL changes. Re-running the workflow is designed to be safe: when the database already matches the file, another run makes no changes. That makes it practical for repeatable deployments, though teams still need to review how proposed changes fit their own release process.

Sqldef supports MySQL, MariaDB, TiDB, PostgreSQL, SQL Server, and SQLite3. Its multi-engine scope is a strong fit for teams working across different relational databases, but support for several engines does not make their SQL interchangeable; the schema still needs to suit its target database.

Key features

• Schema diffing and migrations: Compare the desired schema with the current database and generate DDL changes. This gives teams a SQL-centered alternative to managing each change as a separate migration script.
• Preview and export: Export the current schema, then use dry-run to preview proposed migrations without executing them. This is useful for review before applying changes, although a preview does not itself approve or deploy a change.
• Offline comparison: Compare two SQL files without connecting to a database. That supports schema checks in CI/CD, validation, and migration-script generation when a live database connection is not appropriate.
• Rename annotations: An @renamed annotation documents renames of tables, columns, indexes, and ENUM values, helping sqldef distinguish a rename from a change that would otherwise be treated differently.
• Single-binary distribution: Each database tool is distributed as a standalone binary with no dependencies. Docker images and a GitHub Action for previewing schema changes offer additional ways to fit it into automated workflows.

Pricing

sqldef — free. The open-source CLI tool is available at no charge. There is no paid tier or trial to weigh against a free allowance; the trade-off is that sqldef is a command-line tool rather than a paid, bundled database-management suite.

Platforms

Sqldef supports Linux, macOS, Windows, and self-hosted use. The project provides prebuilt Linux binaries and Docker images, but Debian packages are not currently available. On macOS, a Homebrew tap is available for mysqldef, psqldef, sqlite3def, and mssqldef. Those installation details matter if your team standardizes on a particular package manager.

Who it's for

Choose sqldef if your team is comfortable maintaining schemas in SQL and wants repeatable diffs, previews, and migration generation across supported databases. Its offline comparison and GitHub Action make it especially relevant to teams that want schema checks in CI/CD. It is less suited to readers looking for a graphical database workspace or a workflow built around tools other than SQL files and the command line.

Pros and cons

• Pro: One desired-schema workflow covers six database engines, useful for teams maintaining more than one relational database.
• Pro: Dry-run, offline file comparison, and idempotent runs support review and repeatable automation without requiring every comparison to connect to a live database.
• Pro: Standalone binaries have no dependencies, reducing setup requirements for command-line use.
• Con: The SQL-file and CLI-centered approach expects users to be comfortable with both; it is not presented as a graphical schema editor.
• Con: Linux users cannot install a Debian package, and the macOS Homebrew tap covers the named database tools rather than every possible installation preference.

Alternatives

For a broader comparison, see Database Schema Comparison Tools.

• DBDiff is another free, open-source project for Linux, macOS, and Windows; choose between them based on your preferred project and workflow, since the available description does not establish feature differences.
• Skeema offers a free Community plan with tables, stored procedures and functions, and 18 linter checks for Linux and macOS. Consider it if those listed capabilities are a better match; its Plus plan is $124 a month.
• pgquarrel is free BSD-3-Clause licensed software for Linux, self-hosted use, and Windows. Its narrower platform listing may suit a different deployment environment.
• dbdiff is a free option for Linux, macOS, self-hosted use, and Windows.
• dbForge Studio for PostgreSQL offers a free Express plan with basic functionality and a limited feature set, plus a Standard plan at $89.95 a year. Consider it if a PostgreSQL-specific option with those plan tiers fits your needs better.
• DBC is a free alternative for Linux, macOS, and Windows.
• apgdiff is a free, MIT-licensed PostgreSQL schema diff tool; choose it if you need a tool specifically for PostgreSQL schema diffs.
• GitHub CodeQL has a free plan for research and open-source codebases and a GitHub Code Security plan at $30 a month; consider it when that stated use and plan structure are a closer fit.

Verdict

Sqldef is a strong choice for SQL-fluent teams that want a free, repeatable way to compare and apply schema changes across several relational database engines, with offline checks and previews for automation. Look elsewhere if your priority is a graphical workspace or a database-specific workflow rather than a declarative SQL file and CLI.