What are the best methods for querying and updating a self-relation in Prisma?

Question

What are the best methods for querying and updating a self-relation in Prisma?

I recently obtained some self-relation tables directly from a specific Prisma example.

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 contemplating the most effective way to determine if one user is following another, as well as methods for following and unfollowing. My initial thought is to directly query/update the Follows table, but I'm uncertain if the followedBy and following fields in the User model will automatically update themselves.

javascript database typescript prisma

Answer 1

Answer №1

Consider this scenario:

Adding a new user:

  const createUser = await prisma.user.createMany({
    data: [
      {
        name: 'user1',
      },
      {
        name: 'user2',
      },
      {
        name: 'user3',
      },
    ],
  });

Establishing follow relationships

  const establishFollows = await prisma.follows.createMany({
    data: [
      {
        followerId: 1,
        followingId: 2,
      },
      {
        followerId: 1,
        followingId: 3,
      },
      {
        followerId: 2,
        followingId: 3,
      },
    ],
  });

To determine the followers of user 1, you can do so through both the user and follows models as shown below:

  const findUserFollowers = await prisma.socialUser.findMany({
    where: {
      following: {
        some: {
          followerId: 1,
        },
      },
    },
  });

  console.log('findUserFollowers', findUserFollowers);

  const findFollowsFollowers = await prisma.follows.findMany({
    where: {
      followerId: 1,
    },
    include: {
      following: true,
    },
  });

  console.log('findFollowsFollowers', findFollowsFollowers);

Here is the result:

findUserFollowers [ { id: 2, name: 'user2' }, { id: 3, name: 'user3' } ]

findFollowsFollowers [
  {
    followerId: 1,
    followingId: 2,
    following: { id: 2, name: 'user2' }
  },
  {
    followerId: 1,
    followingId: 3,
    following: { id: 3, name: 'user3' }
  }
]

To handle unfollow actions, the record must be explicitly deleted from the follows table.

Answer 2

Consider this scenario:

Adding a new user:

  const createUser = await prisma.user.createMany({
    data: [
      {
        name: 'user1',
      },
      {
        name: 'user2',
      },
      {
        name: 'user3',
      },
    ],
  });

Establishing follow relationships

  const establishFollows = await prisma.follows.createMany({
    data: [
      {
        followerId: 1,
        followingId: 2,
      },
      {
        followerId: 1,
        followingId: 3,
      },
      {
        followerId: 2,
        followingId: 3,
      },
    ],
  });

To determine the followers of user 1, you can do so through both the user and follows models as shown below:

  const findUserFollowers = await prisma.socialUser.findMany({
    where: {
      following: {
        some: {
          followerId: 1,
        },
      },
    },
  });

  console.log('findUserFollowers', findUserFollowers);

  const findFollowsFollowers = await prisma.follows.findMany({
    where: {
      followerId: 1,
    },
    include: {
      following: true,
    },
  });

  console.log('findFollowsFollowers', findFollowsFollowers);

Here is the result:

findUserFollowers [ { id: 2, name: 'user2' }, { id: 3, name: 'user3' } ]

findFollowsFollowers [
  {
    followerId: 1,
    followingId: 2,
    following: { id: 2, name: 'user2' }
  },
  {
    followerId: 1,
    followingId: 3,
    following: { id: 3, name: 'user3' }
  }
]

To handle unfollow actions, the record must be explicitly deleted from the follows table.

What are the best methods for querying and updating a self-relation in Prisma?

Answer №1

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