Prisma•4mo ago

Representing a User with sub-roles

Hello, I'm trying to figure out the best way to represent this relationship. I know union types aren't possible in the schema but I can define them in the sdl. I'm not sure a union is what I want though, because it adds complexity to the queries. Essentially I have a user. I don't do a lot of business logic in my app with that user though, instead I use other models like "Staff" and "Customer". A user could be a staff OR a customer. During the user creation process I connect either the staff or customer model. However that leads to one being empty and my app having to probe whether a user is staff or customer. I'm currently doing something like this (reason being staff and customer are very different, so this scales better):

model User {
  id                  Int             @id @default(autoincrement())
  createdAt           DateTime        @default(now())
  updatedAt           DateTime        @default(now()) @updatedAt
  email               String          @unique
  hashedPassword      String          @default("")
  salt                String          @default("")
  firstName           String
  staff               Staff?
  customer            Customer?
}

model User {
  id                  Int             @id @default(autoincrement())
  createdAt           DateTime        @default(now())
  updatedAt           DateTime        @default(now()) @updatedAt
  email               String          @unique
  hashedPassword      String          @default("")
  salt                String          @default("")
  firstName           String
  staff               Staff?
  customer            Customer?
}

I've also explored another option where:

model User {
  id                  Int             @id @default(autoincrement())
  createdAt           DateTime        @default(now())
  updatedAt           DateTime        @default(now()) @updatedAt
  email               String          @unique
  hashedPassword      String          @default("")
  salt                String          @default("")
  firstName           String
  userType            UserType
}

model UserType {
  id                  Int             @id @default(autoincrement())
  staff               Staff?
  customer            Customer?
}

model User {
  id                  Int             @id @default(autoincrement())
  createdAt           DateTime        @default(now())
  updatedAt           DateTime        @default(now()) @updatedAt
  email               String          @unique
  hashedPassword      String          @default("")
  salt                String          @default("")
  firstName           String
  userType            UserType
}

model UserType {
  id                  Int             @id @default(autoincrement())
  staff               Staff?
  customer            Customer?
}

But I'm not sure what's best. I wish I could do something like:

  userType            Staff | Customer

  userType            Staff | Customer

What are best practices or recommendations to represent relationships like this?

1 Reply

citrinitas•4mo ago

Nevermind, if anyone ever considers this the issue is that prisma doesn't support polymorphism. I ended up doing this in my user model: @@unique([staffId, customertId]) to ensure user can be only staff or customer. And then in my sdl: union RoleDetails = Staff | Customer union type. So that I can return it in the resolver properly: return { ...user, roleDetails: user.staff || user.customer }; Zenstack apparently supports this: https://zenstack.dev/docs/next/guides/polymorphism

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Representing a User with sub-roles