mysqldef (sqldef)

sqldef inverts the usual migration-file workflow: instead of accumulating a sequence of up/down migration scripts, you maintain a single SQL file describing the schema as it should look. Running mysqldef compares that file against the live database and generates (and, with --apply, runs) exactly the CREATE TABLE, ALTER TABLE, and index statements needed to get there — whatever the database’s starting state. Because the operation is idempotent, running it again against an already-converged database is a no-op, which makes it safe to wire into deploy pipelines. An @renamed annotation lets a table, column, index, or ENUM value rename be expressed explicitly, so sqldef doesn’t mistake a rename for a drop-and-add.

mysqldef is the MySQL, MariaDB, and TiDB variant of the broader sqldef project, which also ships psqldef (PostgreSQL), sqlite3def (SQLite3), and mssqldef (SQL Server) as separate binaries sharing the same approach — an idea originally inspired by Ridgepole’s Ruby-DSL-based schema management, reworked around plain SQL instead. It also supports an offline mode that diffs two SQL files directly without a database connection, useful for CI validation, plus --export and --dry-run workflows. The project is released under the MIT License, with its SQL parser component under the Apache License 2.0.