I have some self-relation tables taken directly from one of Prisma's examples.
model User {
id Int @id @default(autoincrement())
name String?
followedBy Follows[] @relation("follower")
following Follows[] @relation("following")
}
model Follows {
follower User @relation("follower", fields: [followerId], references: [id])
followerId Int
following User @relation("following", fields: [followingId], references: [id])
followingId Int
@@id([followerId, followingId])
}
I am wondering on the best/most idiomatic way to determine whether a user is following another user, as well as operations for following and unfollowing. I'm thinking the best way is to just query/update the Follows table directly, but I'm unsure whether the followedBy and following fields in the User model will automatically update themselves.
Consider this example:
const createUsers = await prisma.user.createMany({
data: [
{
name: 'user1',
},
{
name: 'user2',
},
{
name: 'user3',
},
],
});
const followUsers = await prisma.follows.createMany({
data: [
{
followerId: 1,
followingId: 2,
},
{
followerId: 1,
followingId: 3,
},
{
followerId: 2,
followingId: 3,
},
],
});
const findFollowersThroughUser = await prisma.socialUser.findMany({
where: {
following: {
some: {
followerId: 1,
},
},
},
});
console.log('findFollowersThroughUser', findFollowersThroughUser);
const findFollowersThroughFollow = await prisma.follows.findMany({
where: {
followerId: 1,
},
include: {
following: true,
},
});
console.log('findFollowersThroughFollow', findFollowersThroughFollow);
Here's the output:
findFollowersThroughUser [ { id: 2, name: 'user2' }, { id: 3, name: 'user3' } ]
findFollowersThroughFollow [
{
followerId: 1,
followingId: 2,
following: { id: 2, name: 'user2' }
},
{
followerId: 1,
followingId: 3,
following: { id: 3, name: 'user3' }
}
]
For updating the relations when someone unfollows, the record needs to be explicitly removed from the follows table in this case.