migration-safety-checklist

Database migration safety checklists enforce structural constraints on migration files to prevent data loss, requiring UP/DOWN definitions, safe nullable column additions, non-blocking index creation, and documented rollback procedures before production deployment.

A database schema migration is unsafe if it lacks rollback procedures, adds columns without proper nullable or default handling, or creates blocking indexes that cause long locks and data loss during execution.

To ensure non-blocking index creation, validate that your database migration file follows safe constraint operations and structural recommendations designed to minimize locks during schema changes.

If a schema change is irreversible, you do not need a DOWN migration but must explicitly mark the migration as irreversible and provide rollback documentation to maintain production safety and auditability.

The best way to review a draft migration is to run a safety checklist against it to confirm adherence to structural criteria, validating nullable column handling, index operations, and rollback procedures before deployment.

You should not rely solely on an automated migration safety checklist when handling complex data transformations or non-relational databases, as it specifically validates structural constraints for relational schema changes.