What problem does it solve? Database changes often introduce broken constraints, slow queries, race conditions, or irreversible migrations. This Skill provides structured engineering guidance for schema design, query planning, transaction boundaries, and rollback-safe migrations so persistence changes stay correct and recoverable. ## Core Features & Use Cases - Relational Modeling: Defines entities, keys, foreign keys, nullability, and uniqueness constraints so invariants are enforced by the database rather than application code. - Query and Transaction Design: Selects indexes from real predicates, inspects query plans, prevents N+1 patterns, and sets isolation levels and lock ordering to avoid deadlocks and lost updates. - Migration and Backfill Safety: Plans expand/contract migrations, bounded resumable backfills, rollback paths, and validation queries before destructive changes. - Use Case: When adding a new table with foreign keys to a PostgreSQL schema, use this Skill to design the constraints, choose indexes, and write a reversible migration with a validation query. ## Quick Start Ask the AI to review your schema change or migration plan using the database-engineering skill, including constraints, indexes, transaction behavior, and rollback steps.
