Foreign key value is null

Hi! I have a problem: When I create ManyToOne relationship by @ManyToOne decotator, I want to select foreign key value.

But on field select result is null. How can i get a foreign key value? I`m tryng to use something like this:

@Field(() => User) @ManyToOne(() => User, { nullable: true }) user?: User;

@Field() @Property({ hidden: false, fieldName: “user_id”, unsigned: true }) userId: number; // result is NULL but entity exist (in db FK has value) and other fields has values

Thanks for help!

[B4nan]

Actually there is quite easy way to achieve this, not sure why it did not pop up on my mind before. You can define the userId property as getter that will read the value from user.id:

@ManyToOne(() => User, { nullable: true })
user?: User;

@Property({ persist: false })
get userId(): number {
  return this.user?.id;
}

This is called virtual property in MikroORM: https://mikro-orm.io/docs/defining-entities#virtual-properties

If you want to be able to set to that property, it is a bit more tricky, as you need to set instance of the target entity to the user variable. It can be done via internal entity manager reference if the parent entity is loaded from database (and therefore managed).

@ManyToOne(() => User, { nullable: true })
user?: User;

@Property({ persist: false })
get userId(): number {
  return this.user?.id;
}

set userId(value: number): void {
  this.user = wrap(this).__em!.getReference(User, value); // TODO __em can be undefined if entity not managed
}

[B4nan]

Yes, this is by design.