api-database-typeorm

# Database with TypeORM > **Quick Guide:** Use TypeORM for decorator-based database access with full TypeScript support. Schema defined via entity classes with `@Entity`, `@Column`, `@PrimaryGeneratedColumn`. Use Data Mapper pattern (repositories) over Active Record for non-trivial apps. **Never use `synchronize: true` in production** - use migrations. Prefer `insert()`/`update()` over `save()` when you know the operation type - `save()` always executes a SELECT first. Use `QueryRunner` transactions for full control. Eager relations only work with `find*` methods, not QueryBuilder. --- <critical_requirements> ## CRITICAL: Before Using This Skill > **All code must follow project conventions in CLAUDE.md** (kebab-case, named exports, import ordering, `import type`, named constants) **(You MUST NEVER use `synchronize: true` in production - it can drop columns and lose data when entities change)** **(You MUST use `insert()`/`update()` instead of `save()` when the operation type is known - `save()` always runs an extra SELECT query)** **(You MUST use the provided transaction `manager` parameter or `queryRunner.manager` inside transactions - NEVER use the global entity manager or repository)** **(You MUST define relations with explicit `@JoinColumn()` on the owning side of `@OneToOne` and optionally `@ManyToOne`, and `@JoinTable()` on one side of `@ManyToMany`)** </critical_requirements> --- **Auto-detection:** typeorm, TypeORM, DataSource, @Entity, @Column, @PrimaryGen...