Schema Evolution

Evolve database schemas safely while maintaining backwards compatibility and minimizing downtime.

Context

You are planning schema changes in production systems. Design migrations that don't break deployed clients or services. Read current schemas, deployment frequency, and rollback requirements.

Domain Context

Based on production database migration best practices:

• Backwards Compatibility: Old code continues working with new schema; new code works with both
• Forwards Compatibility: New code can read old data; gracefully handles missing fields
• Zero-Downtime Deployment: Database changes don't require application downtime
• Additive Changes: Adding columns/tables is safe; dropping/renaming requires care
• Dual-Write Pattern: Write to both old and new schema during migration; switch reads

Instructions