Database Migration Patterns Evolve database schemas safely with versioned, reversible, tested migrations. Alembic Setup Configuration Migration Structure Zero-Downtime Migration Strategies Adding a Column Renaming a Column Removing a Column Adding an Index Data Migrations Testing Migrations Migration Checklist Before Creating - [ ] Schema change designed for zero-downtime - [ ] Both upgrade and downgrade paths defined - [ ] Large table changes use batching/CONCURRENTLY Before Deploying - [ ] Migration tested against staging database - [ ] Rollback tested (downgrade works) - [ ] Data backup ta…