task-orchestrator: Skill for Claude Code

Migration Review Framework

Evaluate database migration safety for SQLite-specific constraints. This project uses Flyway migrations with SQLite, which has significant limitations compared to PostgreSQL/MySQL.

Step 1: Identify Schema Changes

Read the changed files and migration SQL to determine:

• New columns — ALTER TABLE ADD COLUMN works in SQLite
• Modified columns — SQLite has NO ALTER COLUMN. Requires table recreation:
  1. Create new table with desired schema
  2. Copy data from old table
  3. Drop old table
  4. Rename new table
• New tables — check foreign key ordering in DirectDatabaseSchemaManager
• Index changes — CREATE INDEX / DROP INDEX work normally

Step 2: SQLite Constraint Check

Verify against known SQLite limitations:

• No ALTER COLUMN — if modifying existing columns, table recreation pattern is used
• No DROP COLUMN in older SQLite versions — check if the Docker image's SQLite supports it
• Foreign key constraints — new tables must be inserted in correct order in DirectDatabaseSchemaManager
• TEXT affinity — SQLite stores all strings as TEXT regardless of declared type
• No concurrent write transactions — migrations must be sequential

Step 3: Data Migration Strategy

For migrations that modify existing data:

• Existing rows handled — default values for new columns, or explicit data migration
• Null safety — new NOT NULL columns require a DEFAULT or data backfill
• Large table performance — SQLite locks the entire database during writes

Step 4: Flyway Integration

• Migration file follows naming: V{N}__{Description}.sql
• Version number is sequential (no gaps, no conflicts with existing migrations)
• Migration is idempotent where possible
• DirectDatabaseSchemaManager updated if new tables are added (insert in FK dependency order)

Step 5: Rollback Considerations

• Can the migration be reversed manually if needed?
• Is the schema change backward compatible with the previous application version?
• Docker volume data survives container restarts — migration is permanent