Agent-Skills.md

Agent Skills: NestJS Database Standards

Implement data access patterns, Scaling, Migrations, and ORM selection in NestJS. Use when implementing TypeORM/Prisma repositories, migrations, or database patterns in NestJS. (triggers: **/*.entity.ts, prisma/schema.prisma, TypeOrmModule, PrismaService, MongooseModule, Repository)

UncategorizedID: hoangnguyen0403/agent-skills-standard/nestjs-database

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hoangnguyen0403/agent-skills-standard
HoangNguyen0403License: Apache-2.0
362103

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pnpm dlx add-skill https://github.com/HoangNguyen0403/agent-skills-standard/tree/HEAD/skills/nestjs/nestjs-database

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skills/nestjs/nestjs-database/SKILL.md

Skill Metadata

Name
nestjs-database
Description
"Implement data access patterns, Scaling, Migrations, and ORM selection in NestJS. Use when implementing TypeORM/Prisma repositories, migrations, or database patterns in NestJS. (triggers: **/*.entity.ts, prisma/schema.prisma, TypeOrmModule, PrismaService, MongooseModule, Repository)"

NestJS Database Standards

Priority: P0 (FOUNDATIONAL)

Database integration patterns and ORM standards for NestJS applications.

Selection Strategy

See references/persistence_strategy.md for database selection matrix and scaling patterns (Connection Pooling, Sharding).

Patterns

  • Repository Pattern: Isolate database logic.
    • TypeORM: Inject @InjectRepository(Entity).
    • Prisma: Create a comprehensive PrismaService.
  • Abstraction: Services should call Repositories, not raw SQL queries.

Configuration (TypeORM)

  • Async Loading: Always use TypeOrmModule.forRootAsync to load secrets from ConfigService.
  • Sync: Set synchronize: false in production; use migrations instead.

Migrations

  • Never use synchronize: true in production.
  • Generation: Whenever a TypeORM entity (.entity.ts) is modified, a migration MUST be generated using pnpm migration:generate.
  • Audit: Always inspect the generated migration file to ensure it matches the entity changes before applying.
  • Production Strategies:
    • CI/CD Integration (Recommended): Run pnpm migration:run in a pre-deploy or post-deploy job (e.g., GitHub Actions, GitLab CI). Ensure the production environment variables are correctly set.
    • Manual SQL (For restricted DB access): Use typeorm migration:show to get the SQL or simply copy the up method's SQL into a management tool (like Supabase SQL Editor). Always track manual runs in the migrations metadata table.
  • Zero-Downtime: Use Expand-Contract pattern (Add -> Backfill -> Drop) for destructive changes.
  • Seeding: Use factories for dev data; only static dicts for prod.

Best Practices

  1. Pagination: Mandatory. Use limit/offset or cursor-based pagination.
  2. Indexing: Define indexes in code (decorators/schema) for frequently filtered columns (where, order by).
  3. Transactions: Use QueryRunner (TypeORM) or $transaction (Prisma) for all multi-step mutations to ensure atomicity.

Anti-Patterns

  • No synchronize in production: Use explicit migrations; synchronize: true drops and recreates columns.
  • No raw entity returns from services: Map to DTOs before leaving the service layer.
  • No unpaginated list queries: All list endpoints must implement limit/offset or cursor pagination.