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Adoption Guide

Adopt nest-drizzle-native in small steps. The package should replace manual Nest provider wiring, not your Drizzle schemas or query style.

Start With One Client​

Before:

export const DATABASE = Symbol('DATABASE');

@Module({
  providers: [
    {
      provide: DATABASE,
      useFactory: () => drizzle(pool, { schema }),
    },
  ],
  exports: [DATABASE],
})
export class DatabaseModule {}

After:

@Module({
  imports: [
    DrizzleModule.forRoot({
      schema,
      connection: drizzle(pool, { schema }),
      shutdown: () => pool.end(),
    }),
  ],
})
export class DatabaseModule {}

Consumers can move from custom tokens to @InjectDrizzle() one provider at a time.

Keep Schemas Unchanged​

Do not rewrite Drizzle schemas as classes or decorators. Keep standard Drizzle table definitions in place and pass the schema object into DrizzleModule.

export const users = pgTable('users', {
  id: serial('id').primaryKey(),
  email: text('email').notNull(),
});

Introduce Repositories Gradually​

Use repositories when query code is shared or complex. Leave simple services with direct @InjectDrizzle() injection until a repository boundary improves the design.

@DrizzleRepository()
export class UsersRepository {
  constructor(@InjectDrizzle() private readonly db: AppDatabase) {}

  findByEmail(email: string) {
    return this.db.query.users.findFirst({
      where: (users, { eq }) => eq(users.email, email),
    });
  }
}

Register repositories through DrizzleModule.forFeature() in the feature module that owns them.

Migrate Validation Separately​

Do not mix database provider adoption with validation rewrites. Keep existing DTOs, pipes, and Swagger decorators working first. Move to optional drizzle-zod patterns only in a separate PR if the application has chosen that validation style.

Add Transactions Last​

@Transactional() relies on the CLS transaction stack. Add it after the Drizzle client is registered through package tokens and after the service boundary is clear.

The usual order is:

  1. Register the Drizzle client with DrizzleModule.
  2. Move shared query code into repositories.
  3. Add real integration tests for the workflows that need rollback.
  4. Configure @nestjs-cls/transactional.
  5. Add @Transactional() at service methods that own the unit of work.

Migration PR Shape​

Keep adoption PRs narrow:

  • One database module or feature module at a time.
  • No schema rewrites.
  • No broad validation migration in the same PR.
  • No raw SQL string interpolation.
  • Include a smoke test or focused unit test for the moved provider boundary.

This keeps the migration reversible and makes review about Nest integration rather than unrelated application behavior.