Using explicit Many to Many Relation in Prisma - many-to-many

Question

I have the following User and Group models that share a many-to-many relation:
model User {
id String #id #default(uuid())
email String #unique
groups UsersGroups[]
##map("user")
}
model Group {
id String #id #default(uuid())
name String
users UsersGroups[]
##map("group")
}
model UsersGroups {
user User #relation(fields: [userId], references: [id])
userId String #map(name: "user_id")
group Group #relation(fields: [groupId], references: [id])
groupId String #map(name: "group_id")
##id([userId, groupId])
##map("users_groups")
}
I'm having trouble using the connect API in Prisma to connect the users and groups. Here's what I have:
await prisma.group.update({
where: {
id: groupId,
},
data: {
users: {
connect: users.map((user) => ({ id: user.id })),
},
},
include: { users: true },
});
That doesn't work and here is the error I'm getting in the console:
PrismaClientValidationError:
Invalid `prisma.group.update()` invocation:
{
where: {
id: '64ce24c7-3054-42f2-b49f-4cdb52cf1bc7'
},
data: {
users: {
connect: [
{
id: '0b3f4a51-0efe-4b0a-8763-e71bc8091b86'
~~
}
]
}
},
include: {
users: true
}
}
Unknown arg `id` in data.users.connect.0.id for type UsersGroupsWhereUniqueInput. Available args:
type UsersGroupsWhereUniqueInput {
userId_groupId?: UsersGroupsUserIdGroupIdCompoundUniqueInput
}
From that above, it looks as though it's attempting to connect a user with id: '0b3f4a51-0efe-4b0a-8763-e71bc8091b86' (which is a user that exists) to the group with id: '64ce24c7-3054-42f2-b49f-4cdb52cf1bc7' (which also exists).
I'd be very grateful if someone could point out where I'm going wrong as I've been going in circles with this for a while now...

Answer 1

You are using an explicit many-to-many relation, cf. https://www.prisma.io/docs/concepts/components/prisma-schema/relations/many-to-many-relations#explicit-many-to-many-relations
I.e. you have defined the model UsersGroups yourself.
As a consequence, you would have to manage/create the records in this table yourself and connect it with the entry in the third table, e.g. like this (haven't tested it):
prisma.group.update({
where: {
id: groupId,
},
data: {
users: { create: { user: { connect: { id: userId } } } },
},
include: { users: true },
});
or if you want to loop over an list:
prisma.group.update({
where: {
id: groupId,
},
data: {
users: {
create: users.map((user) => ({
user: { connect: { id: user.id } },
})),
},
},
include: { users: true },
});
I would suggest to replace groups UsersGroups[] and users UserGroups[] with
userGroups UsersGroups[] in the schema to make it clearer.
As an alternative to explicit relationships you could try to use implicit many-to-many relations in the schema like this:
model User {
id String #id #default(uuid())
email String #unique
groups Group[]
##map("user")
}
model Group {
id String #id #default(uuid())
name String
users User[]
##map("group")
}
cf. https://www.prisma.io/docs/concepts/components/prisma-schema/relations/many-to-many-relations#implicit-many-to-many-relations