schema-evolution

What problem does it solve?

This Skill prevents production incidents by guiding you to evolve a database schema over time while keeping deployed application code working through the full expand → migrate → contract sequence.

Core Features & Use Cases

• Expand/Contract (Parallel Change): Add new structures compatibly, migrate safely across deploys, then remove old structures only when the system is fully switched.
• Compatibility Envelope & Deploy Ordering: Define which code versions can run against which intermediate schema states, including migration-first vs code-first vs coordinated multi-step changes.
• Change-Type Safety Guidance: Use an explicit safety matrix for common operations like renames, type changes, constraint tightening, and index/foreign key additions.
• Dual-write / Dual-read Transitions: Apply non-trivial transitions using staged reads/writes and defined criteria for advancing phases.
• Verification & Rollback Discipline: Provide concrete verification checks to decide when it’s safe to contract and when rollback is still possible.

Quick Start

Use schema-evolution to plan an expand → migrate → contract sequence for renaming a column from name to full_name without breaking deployed services.