prisma-expert

name	prisma-expert
type	reference
description	Provides Prisma ORM patterns for schema design, migrations, query optimization, and relation modeling. Use when working with Prisma schema files (schema.prisma) or when the user mentions Prisma, Prisma migrations, or Prisma queries.
paths	["**/prisma/**","**/*.prisma","**/schema.prisma"]
when_to_use	When working with Prisma ORM for schema design, migrations, query optimization, or troubleshooting database operations
allowed-tools	Read, Glob, Grep, Write, Edit, Bash
user-invocable	true
effort	3

Prisma Expert

Critical rules (non-obvious)

• Never use migrate dev in production — use migrate deploy; migrate dev can reset data
• Singleton client in serverless — new PrismaClient() per request exhausts connections; use global singleton
• include vs select: include: { posts: true } fetches ALL post fields; use select to limit
• $queryRaw returns unknown[] — you must cast with as or validate; Prisma can't infer raw query types
• Missing @relation on both sides causes "The relation is not defined on both sides" runtime error

Schema: canonical model structure

model User {
  id        String   @id @default(cuid())
  email     String   @unique
  role      Role     @default(USER)
  posts     Post[]   @relation("UserPosts")
  profile   Profile? @relation("UserProfile")
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  @@index([email])
  @@map("users")
}

model Post {
  id       String  @id @default(cuid())
  title    String
  content  String?
  published Boolean @default(false)
  author   User    @relation("UserPosts", fields: [authorId], references: [id], onDelete: Cascade)
  authorId String

  @@index([authorId])
  @@map("posts")
}

enum Role { USER ADMIN MODERATOR }

Query optimization: N+1 fix

// ❌ N+1
const users = await prisma.user.findMany();
for (const user of users) {
  const posts = await prisma.post.findMany({ where: { authorId: user.id } });
}

// ✅ Include (fetches all post fields)
const users = await prisma.user.({ : { :  } });


 users =  prisma..({
  : {
    : , : ,
    : { : { : , :  } },
  },
});


 result =  prisma.<{ : ; :  }[]>;