What is schema migration versioning and why is it important?

Schema migration versioning tracks database schema changes as ordered, versioned files (migration scripts) stored in version control alongside application code. Each migration has an up (apply change) and down (revert change) operation. A migrations table in the database records which migrations have been applied. This ensures: all environments (development, staging, production) have the same schema; team members can reproduce the schema from scratch; schema changes are reviewed in code review; and rollback is possible. Tools: Flyway, Liquibase (Java), Alembic (Python), Rails migrations, Golang-migrate. Without versioning, schemas between environments diverge and deployments break.