sdlc-nest-data-layer

ORM patterns for NestJS: TypeORM, Prisma, Mongoose. Covers entities, repositories, transactions, migrations, common pitfalls (N+1, cascade deletes, transaction boundaries). Use this skill to: - Detect which ORM the project uses and apply matching patterns. - Define entities/schemas with the right decorators. - Inject repositories or Prisma client correctly. - Run transactions at the service boundary. - Write migrations that round-trip cleanly. Do NOT use this skill for: - Module/DI patterns (see nest-conventions). - Decorator usage broadly (see decorator-patterns). - Non-ORM raw SQL (rare; flag in BLOCKERS if needed).