Same type relationships in GraphQL / Prisma

Question

I am trying to create a one-to-many relation of the same type. In this case, a user can report to one user and in turn have many users reporting to them.

My data model currently looks like this:

type User {
  id: ID! @id
  name: String!
  email: String! @unique
  reportsTo: User @relation(name: "UserReports")
  reports: [User] @relation(name: "UserReports")
}

I expect adding a userId to reportsTo should add the corresponding user's ID to reports.

However, adding a userId to reportsTo is adding the userId to the same user's reports, rather than other users reports.

score 0 · Answer 1 · answered Aug 12 '19 at 23:28

You can't have a relationship with different elements of the one type. A relation is connecting two different types so we know they share information. Therefore we need to create some addition types that we can base a relationship on.

I've created two different types, one a "supervisor" who is a user who supervises other users, but we will have those users as a second type, "supervisee". Each user can be both a supervisor and a supervisee. There is a relation between a user and each of these two types and a relation between these two types as well.

This is the datamodel:

type User {
  id: ID! @id
  name: String!
  email: String! @unique
  supervisor: Supervisor @relation(name: "UserToSupervisor")
  supervisee: Supervisee @relation(name: "UserToSupervisee")
}

type Supervisor {
  id: ID! @id
  user: User! @relation(name: "UserToSupervisor")
  supervisees: [Supervisee!]! @relation(name: "SupervisorToSupervisee")
}

type Supervisee {
  id: ID! @id
  user: User! @relation(name: "UserToSupervisee")
  supervisor: Supervisor! @relation(name: "SupervisorToSupervisee")
}

You must view the "supervisor" field in user not as who that users supervior is, but that the user might be a supervisor themselves. This is also the case with supervisee. Basically supervisor and supervisee are extensions of user and the working relationship between them is defined between those two types.

Same type relationships in GraphQL / Prisma

1 Answers1