db-review

name	db-review
description	Reviews database schemas, migrations, and queries for correctness, performance, data integrity, and naming conventions. Checks indexes, constraints, migration safety, and ORM usage patterns.
argument-hint	[path-to-schema-migration-or-query-files]
user-invocable	true
allowed-tools	Read, Glob, Grep
context	fork
agent	data-engineer
effort	2
when_to_use	When reviewing database schemas, migrations, or queries for correctness, performance, and data integrity

When this skill is invoked:

1. Read the target schema, migration, or query files in full.

2. Evaluate schema design:

   • All tables have a primary key
   • Tables have created_at and updated_at columns
   • Foreign key relationships defined with proper constraints
   • Column types are appropriate (don't use VARCHAR(255) for everything)
   • NULL vs NOT NULL is intentionally chosen and documented
   • Enum types used for fixed sets of values

3. Evaluate indexing strategy:

   • Every foreign key column is indexed
   • Columns in frequent WHERE, ORDER BY, or JOIN conditions are indexed
   • Composite indexes match the query patterns
   • No over-indexing (too many indexes slow writes)
   • Unique constraints used where business rules require uniqueness

4. Evaluate migration safety:

   • Migration is reversible (has a down/rollback script)
   • Adding columns with defaults is safe for zero-downtime
   • Removing columns uses soft-delete / multi-phase approach
   • Renaming columns uses multi-phase migration (add → backfill → drop old)
   • Large table operations consider locking implications

5. Evaluate data integrity:

   • Check constraints for value ranges where appropriate
   • No orphaned records possible (foreign keys or enforced at app layer)