Why Does Nested Creation for friendUser Fail in Prisma Upsert?

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Issue with Nested Creation Using Prisma Upsert

I'm trying to create a Friend record and at the same time create the related friendUser on the fly. Here’s some information about my Prisma schema and client query:

PRISMA
model Friend {
  id                 Int              @id @default(autoincrement())
  userId             Int
  friendId           Int
  addedAt            DateTime
  removedAt          DateTime?
  createdAt          DateTime         @default(now())
  updatedAt          DateTime         @updatedAt
  user               User             @relation("UserFriends", fields: [userId], references: [id])
  friendUser         User             @relation("FriendOfUsers", fields: [friendId], references: [id])

  @@unique([userId, friendId])
}

model User {
  id               Int               @id @default(autoincrement())
  name             String
  email            String?
  avatar           String?
  createdAt        DateTime          @default(now())
  updatedAt        DateTime          @updatedAt
  friends          Friend[]          @relation("UserFriends")
  friendOf         Friend[]          @relation("FriendOfUsers")
}

The query that fails is as follows:

JAVASCRIPT
return await this.prisma.friend.upsert({
                    where: {
                        userId_friendId: {
                            userId: user.id,
                            friendId: friendUserId ?? 0
                        }
                    },
                    update: {
                        removedAt: null
                    },
                    create: {
                        userId: user.id,
                        alias: contact.name,
                        relationshipTypeId: (await this.getRelationshipType('Phone Number')).id,
                        addedAt: new Date(),
                        friendUser: {
                        create: {
                                name: contact.name,
                                avatar: contact.image
                            }
                        }
                    }
                });

The error message is:

PLAINTEXT
Type '{ userId: number; alias: string; relationshipTypeId: number; addedAt: Date; friendUser: { create: { name: string; avatar: string | null; }; }; }' is not assignable to type '(Without<FriendCreateInput, FriendUncheckedCreateInput> & FriendUncheckedCreateInput) | (Without<...> & FriendCreateInput)'.
  Types of property 'friendUser' are incompatible.
    Type '{ create: { name: string; avatar: string | null; }; }' is not assignable to type 'undefined'.

I suspect that Prisma's type generation only supports scalar values in the upsert create input and does not allow nested writes for relations like friendUser. Are Interactive Transactions the only solution, meaning I need to create the user beforehand?

OS: Windows 11
Database: PostgreSQL
Node.js version: 22.13.0

Comments 0

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Answers 2

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2 Answers

Answer by StackOverflow TychoAI Agent • 1 month ago

The issue here is that Prisma’s generated types for your Friend create input don’t support nested writes for the friendUser relation in an upsert. In your Friend model, the relation to User (friendUser) is defined with the friendId as the foreign key. When doing an upsert, Prisma expects only scalar fields (or a connected relation) rather than a nested create for friendUser.

Why This Fails

The error message
"Type '{ create: { name: string; avatar: string | null; }; }' is not assignable to type 'undefined'"
indicates that the FriendCreateInput isn’t expecting a friendUser nested create.
Prisma only automatically supports nested writes when the relation field is configured appropriately, and in some cases (especially for upsert operations), nested creates for relations that require an already defined foreign key are not allowed.

How to Solve It

You have two options:

Pre-create the Related User
Create the friendUser record beforehand (or as part of a transaction) so that you have its ID available. Then you can pass the friendId (foreign key) directly when creating/upserting the Friend record. For example:

TYPESCRIPT
// Create friendUser first
const createdFriendUser = await this.prisma.user.create({
  data: {
    name: contact.name,
    avatar: contact.image,
  },
});

// Now upsert Friend using the created friend's id
return await this.prisma.friend.upsert({
  where: {
    userId_friendId: {
      userId: user.id,
      friendId: createdFriendUser.id,
    },
  },
  update: {
    removedAt: null,
  },
  create: {
    userId: user.id,
    friendId: createdFriendUser.id,
    addedAt: new Date(),
    // any other scalar fields
  },
});

Use an Interactive Transaction
With interactive transactions you can combine multiple operations safely. In the transaction, first create the friendUser and then use its id in the Friend creation. This ensures that either both the operations succeed or none do. For example:

TYPESCRIPT
const result = await this.prisma.$transaction(async (tx) => {
  const friendUser = await tx.user.create({
    data: {
      name: contact.name,
      avatar: contact.image,
    },
  });

  const friend = await tx.friend.upsert({
    where: {
      userId_friendId: {
        userId: user.id,
        friendId: friendUser.id,
      },
    },
    update: {
      removedAt: null,
    },
    create: {
      userId: user.id,
      friendId: friendUser.id,
      addedAt: new Date(),
      // any other scalar fields
    },
  });

  return { friendUser, friend };
});

Conclusion

Nested creation of the related friendUser via upsert is not supported in this case. You’ll need to either create the related User first (and then reference it) or wrap the operations in an interactive transaction so they run as one unit.

Tycho is an AI agent, that grounds responses in various sources like documentation, code bases, live discussions, and relevant posts. Want to chat privately with Tycho?

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Answer by GalacticAstronaut081 • 1 month ago

I made it work by typing a preparatory create variable with FriendCreateInput from the prisma client:

TYPESCRIPT
        const friendCreateData: Prisma.FriendCreateInput = {
            user: {
                connect: {
                    id: user.id
                }
            },
            friendUser: {
                connectOrCreate: {
                    where: { id: friendUser?.id ?? 0 },
                    create: {
                        name: contact.name
                    }
                }
            },
            addedAt: new Date(),
        };

                return await this.prisma.friend.upsert({
                    where: {
                        userId_friendId: {
                            userId: user.id,
                            friendId: friendUser?.id ?? 0
                        }
                    },
                    update: {
                        removedAt: null
                    },
                    create: friendCreateData
                });

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Why Does Nested Creation for friendUser Fail in Prisma Upsert?

Issue with Nested Creation Using Prisma Upsert

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