TypeORM Entity Generator

TypeORM is a TypeScript ORM that supports Active Record and Data Mapper patterns. It works with PostgreSQL, MySQL, MariaDB, SQLite, Microsoft SQL Server, Oracle, MongoDB, and more. It integrates tightly with TypeScript decorators, making entity definitions readable and type-safe. It's commonly used with NestJS.

@PrimaryGeneratedColumn('increment') creates an auto-incrementing integer PK (SERIAL in PostgreSQL, AUTO_INCREMENT in MySQL). @PrimaryGeneratedColumn('uuid') generates a UUID v4 as the PK — better for distributed systems where global uniqueness matters. Use integers for simplicity and performance; UUIDs for distributed or external-facing IDs.

@CreateDateColumn automatically sets the column to the current timestamp when the entity is first inserted. @UpdateDateColumn automatically updates to the current timestamp on every save/update. Both are stored as TIMESTAMP (or DATETIME in MySQL) and require no manual handling in your application code.

The json type maps to JSON in MySQL and JSONB in PostgreSQL by default. You can store arbitrary JavaScript objects. Use @Column({ type: 'json', nullable: true }) for optional JSON fields. For PostgreSQL-specific JSONB with full indexing support, use @Column({ type: 'jsonb' }) explicitly.

@Entity() without arguments uses the class name (lowercased) as the table name. @Entity('orders') explicitly sets the table name to 'orders'. Best practice is to always set explicit table names to avoid surprises from class renaming. TypeORM also supports schema-qualified names: @Entity({ schema: 'public', name: 'orders' }).