CODEWITHSUNDEEP
databasepostgresqlormnestjstypeorm
Ambroise Rabier
Ambroise Rabier

Reputation: 4102

How to make unique constraint on ONE to MANY relationship?

I have two entities: project and actor.

export abstract class BaseEntityModel {
  @PrimaryGeneratedColumn()
  id: number;
}

@Entity()
export class Project extends BaseEntityModel {
    @Column()
    title: string;

    @OneToMany(type => Actor, actor => actor.project)
    @JoinColumn()
    actors: Actor[];
}

@Entity()
export class Actor extends BaseEntityModel {
    @Column({unique: true}) 
    title: string;

    @ManyToOne(type => Project, project => project.actors)
    project: Project;
}

I want unique actor title per project, but not across database.

OK

projects: [
  {
    title: "webapp",
    actors: [
      {
        title: "dev"
      }
    ]
  },
  {
    title: "json-parser",
    actors: [
      {
        title: "dev"
      },
      {
        title: "target"
      }
    ]
  }
]

NOT OK

projects: [
  {
    title: "webapp",
    actors: [
      {
        title: "dev"
      },
      {
        title: "dev"
      }
    ]
  },
  {
    title: "json-parser",
    actors: [
      {
        title: "dev"
      },
      {
        title: "target"
      }
    ]
  }
]

@Column({unique: true}) work as unique across table, that is not what I want. There is also class decorator @Unique(['title']), but it seems to be doing the same.

Is there something from TypeORM that I can use, or do I have to check myself if the actor.title already exist in project. To avoid duplicated actor.title in the same project. While keeping the possibility to have multiple time the same actor.title across the database?

Note that Actor entity should not be shared across projects (no many to many relationship).

Upvotes: 3

Views: 3801

Answers (1)

Ambroise Rabier
Ambroise Rabier

Reputation: 4102

Adding @Unique(['title', 'project']) class decorator to Actor seems to be what I was looking for, note that I had "corrupted" my database somehow and migration worked correctly only after deleting/creating it.

Upvotes: 7

Related Questions