Introduction

The relationshipField decorator in Graphweaver allows you to establish relationships between GraphQL entities. It provides a convenient way to define and configure relationships, enabling you to link entities and query related data.

Usage

We are going to work through an example where we connect a Task to a single User and a collection of Tags.

To use the relationshipField decorator, follow these steps:

• Import the relationshipField decorator and the entities you want to link:

import { RelationshipField } from '@exogee/graphweaver';
import { Field, ObjectType } from 'type-graphql';

// Import the related entities (e.g., User and Tag)
import { User } from '../user';
import { Tag } from '../tag';

• Create two properties on the Task entity. One for User and One for Tag. Decorate the field using the relationshipField decorator:

@Entity('Task', { provider: taskProvider })
export class Task extends GraphQLEntity<OrmTask> {
  // Other fields and decorators...

  @RelationshipField<Task>(() => User, { id: 'userId' })
  user!: User;

  @RelationshipField<Tag>(() => [Tag], { relatedField: 'tasks' })
  tags!: Tag[];

  // Other entity code...
}

In this example, we're using a Task entity and establishing relationships with the User and Tag entities.

• Configure the relationshipField decorator:
  • For linking a single entity (from Task to User):
    • Specify the related entity class using the () => RelatedEntity syntax.
    • Specify the foreign key field using the id property. This is used to match the relationship between the entities. Here it is using the userId field which is on Task.userId
• For linking a collection of entities:
  • Specify the related entity class using the () => [RelatedEntity] syntax.
  • Specify the relatedField property with the name of the field on the related entity that represents the inverse relationship. In this case its the reverse relationship and which is Tag.tasks.