TypeORM: Add Columns with Array Data Type

Updated: August 31, 2022 By: A Goodman Post a comment

When using TypeORM, it’s possible to define columns with the array data type.

If you want to add a column that stores arrays of numbers, you can define it like so:

@Column('integer', {
    array: true, // this is supported by postgreSQL only
    nullable: true,
})
sizes: number[];

In case you need a column that stores arrays of strings, you can define it like this:

@Column('simple-array', { nullable: true })
colors: string[];

It is essential to be aware that you MUST NOT have any comma in any element of your array.

The example below creates a table named products whose some columns’ types are array:

// Product entity
import {
  Entity,
  PrimaryGeneratedColumn,
  Column,
  CreateDateColumn,
} from 'typeorm';

@Entity({name: 'products'})
export class Product {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  // array of numbers
  @Column('integer', {
    array: true, // this is supported by postgres only
    nullable: true,
  })
  sizes: number[];

  // array of strings
  @Column('simple-array', { nullable: true })
  colors: string[];

  @Column({ type: 'simple-array', nullable: true })
  materials: string[];

  @CreateDateColumn()
  createdAt: Date;
}

And here’s how we save a new record:

const productRepository = dataSource.getRepository(Product);
const product = new Product();
product.name = 'KindaCode.com';
product.sizes = [1, 2, 3];
product.colors = ['red', 'blue', 'green'];
product.materials = ['wood', 'metal', 'plastic'];

await productRepository.save(product);

When viewing the data you’ve added to your database, you’ll see something like this: