Primary key as join column in 1:1 relation

Issue type:

[x] question [?] bug report [ ] feature request [ ] documentation issue

Database system/driver:

[ ] cordova [ ] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [x] postgres [ ] cockroachdb [ ] sqlite [ ] sqljs [ ] react-native [ ] expo

TypeORM version:

[ ] latest [ ] @next [x] 0.2.12

Steps to reproduce or a small repository showing the problem:

Let’s say I have the following two entities (simplified for demonstration purposes):

@Entity()
export class A {
  @PrimaryGeneratedColumn('uuid')
  readonly id: string;

  @OneToOne(() => B, b => b.a, { nullable: true })
  readonly b: B | null;
}

@Entity()
export class B {
  @PrimaryColumn()
  readonly id: string;

  @OneToOne(() => A, a => a.b)
  @JoinColumn({ name: 'id' })
  readonly a: A;
}

Running schema:log or migration:generate on a blank database shows that TypeORM generates both a primary key as well as a unique key for B.id. It’s clear why TypeORM would want to add a unique key constraint on a column which represents a 1:1 relation in general, but in this case the column already has a primary key and therefore I’d think the unique key is redundant. If my logic is sound then this is a bug 😃 it also happens if entity B already existed previously and now I’m adding entity A and changing B.id from a generated UUID primary column to a join column for the new relation - the migration that is generated drops the default value of B.id, creates the appropriate table for A and the foreign key B("id") references A("id"), but also creates the unique key while leaving the existing primary key in place. (One other thing it does is DROP SEQUENCE "b_id_seq", which never existed as B.id is a UUID column and not a serial, but that’s a separate issue.)

The question is therefore: is this the expected behaviour (as in “expected by design”)? If so, why is that? Why wouldn’t the primary constraint do the job? And if not, well, then like I said, I’d like to report a beetle sighting 😃

[bmoe24x]

+1 we are having the same issue. Don’t want a redundant column if both entities are related based on their primary key.

[roylee0704]

@jahudka try specify classB.id column as type ‘uuid’

@Entity()
export class A {
  @PrimaryGeneratedColumn('uuid')
  readonly id: string;

  @OneToOne(() => B, b => b.a, { nullable: true })
  readonly b: B | null;
}

@Entity()
export class B {

  @PrimaryColumn('uuid')
  readonly id: string;

  @OneToOne(() => A, a => a.b)
  @JoinColumn({ name: 'id' })
  readonly a: A;
}