Liquibase
Database migration tool. Nathan Voxland, 2006. Define schema changes in XML/YAML/JSON/SQL changesets, run them in order, track applied ones in a metadata table.
Competitor: Flyway (more SQL-focused). Liquibase supports rollback (Flyway doesn't officially). Strong in Java enterprise with Spring Boot integration. Cross-database: PostgreSQL, MySQL, Oracle, SQL Server, etc. — abstract syntax can be ported. Pricing: Community free, Pro/Enterprise with extra features (parallel execution, diff). Modern alternatives for specific stacks: Prisma Migrate (Node), Alembic (Python), ActiveRecord Migrations (Rails), Atlas (open source, schema-as-code).