ReferencesMany

Below is how you can define a ReferencesMany relationship.

@Definition()
export class Tag {
  @Id()
  id: ObjectId;
 
  @Property()
  name: string;
}
 
@Definition()
export class Product {
  @Id()
  id: ObjectId;
 
  @Property()
  name: string;
 
  @Property({
    type: () => [GraphQLObjectId],
    nullable: true,
    db: { type: [ObjectId], default: [] },
  })
  tagIds: ObjectId[];
 
  @ReferencesMany(() => Tag, { from: 'tagIds', allowCreateWithin: true })
  tags: Tag[];
}

In the above example, we define a Product references many Tag. The tagIds field is used to store the Tag ids. The tags field is used to resolve the Tag objects. The difference between ReferencesMany and HasMany is that a tag can be referenced by multiple products whereas a product can only belong to one store.

Create API

mutation {
  createProduct(input: {
    name: "Product 1"
    tagIds: ["000000000000000000000000"]
    tags: [
      { name: "Tag 1" }
    ]
  }) {
    id
    name
    tagIds
    tags {
      id 
      name
    }
  }
}

In this example, product will be created with 2 tags. One is the pre-existing tag with id 000000000000000000000000 and the other is a new tag with name Tag 1.

Resolve fields

@Definition()
export class Product {
  @ReferencesMany(() => Tag, { from: 'tagIds', noPopulation: true })
  tags: Tag[];
}

Ensure relationship

By default, you cannot remove a Tag if it is associated with any Products. To allow the removal of a Tag even when it is associated with Products, you can set skipRelationCheckOnRemove to true in the options;