undeexcepturi/docs/versioned_docs/version-4.5/using-bigint-pks.md

TypeScript ORM for Node.js based on Data Mapper, Unit of Work and Identity Map patterns. Supports MongoDB, MySQL, PostgreSQL and SQLite databases as well as usage with vanilla JavaScript.

---
title: Using native BigInt PKs (MySQL and PostgreSQL)
---

You can use `BigIntType` to support `bigint`s. By default it will represent the value as a `string`.

```typescript
@Entity()
export class Book {

  @PrimaryKey({ type: BigIntType })
  id: string;

}
```

If you want to use native `bigint` type, you will need to create new type based on the `BigIntType`:

```typescript
export class NativeBigIntType extends BigIntType {

  convertToJSValue(value: any): any {
    if (!value) {
      return value;
    }

    return BigInt(value);
  }

}

@Entity()
export class Book {

  @PrimaryKey({ type: NativeBigIntType })
  id: bigint;

}
```