How to fix P2017: The records for relation {relation_name} between the {parent_name} and {child_name} models are not connected. in Prisma

// First, fetch the parent record to see if relation exists
const user = await prisma.user.findUnique({
  where: { id: userId },
});

// Then, verify the related record exists
const profile = await prisma.profile.findUnique({
  where: { id: profileId },
});

if (!profile) {
  throw new Error(`Profile with ID ${profileId} not found`);
}

// Now it's safe to connect
await prisma.user.update({
  where: { id: userId },
  data: {
    profile: { connect: { id: profileId } },
  },
});

// Fetch current state
const post = await prisma.post.findUnique({
  where: { id: postId },
  select: { authorId: true }, // Only select what you need
});

// Only disconnect if the relation exists
if (post?.authorId) {
  await prisma.post.update({
    where: { id: postId },
    data: {
      author: { disconnect: true },
    },
  });
}

// For one-to-many relations, set the FK to null
await prisma.post.update({
  where: { id: postId },
  data: {
    authorId: null, // Direct scalar assignment—no error even if already null
  },
});

// For many-to-many relations, use set: []
await prisma.tag.update({
  where: { id: tagId },
  data: {
    posts: { set: [] }, // Remove all connected posts
  },
});

await prisma.user.update({
  where: { id: userId },
  data: {
    profile: {
      connectOrCreate: {
        where: { id: profileId },
        create: {
          bio: "Default bio",
          // ... other required fields
        },
      },
    },
  },
});

model User {
  id        String   @id @default(cuid())
  posts     Post[]   // Relation field
}

model Post {
  id        String   @id @default(cuid())
  authorId  String   // Foreign key scalar
  author    User     @relation(fields: [authorId], references: [id])
}

model User {
  id           String              @id @default(cuid())
  memberships  GroupMembership[]   // Relation to junction table
}

model Group {
  id           String              @id @default(cuid())
  memberships  GroupMembership[]   // Relation to junction table
}

model GroupMembership {
  id      String @id @default(cuid())
  userId  String
  groupId String
  user    User   @relation(fields: [userId], references: [id], onDelete: Cascade)
  group   Group  @relation(fields: [groupId], references: [id], onDelete: Cascade)
}

await prisma.groupMembership.create({
  data: {
    userId: userId,    // Ensure this user exists
    groupId: groupId,  // Ensure this group exists
  },
});

const prismaWithMiddleware = prisma.$extends({
  query: {
    $allModels: {
      async update({ args, query }) {
        try {
          return await query(args);
        } catch (error) {
          if (error.code === "P2017") {
            // Fetch current state and retry without disconnect
            console.warn(`P2017 detected for ${args.model}, retrying...`);
            // Handle gracefully based on your app logic
          }
          throw error;
        }
      },
    },
  },
});