Attributes

Model and field attributes for constraints, indexes, and database mappings.

Overview

Attributes modify the behavior of fields and models. Field attributes start with @, while model (block) attributes start with @@.

Field Attributes

@id

Defines the primary key:

model User {
  id Int @id @default(autoincrement())
}

@default

Sets default value for a field:

model Post {
  id        Int      @id @default(autoincrement())
  published Boolean  @default(false)
  createdAt DateTime @default(now())
  uuid      String   @default(uuid())
  cuid      String   @default(cuid())
}

Default functions:

• autoincrement() - Auto-incrementing integer
• now() - Current timestamp
• uuid() - Generate UUID
• cuid() - Generate CUID
• dbgenerated("SQL") - Database default expression

model Status {
  id        BigInt @id @default(dbgenerated("timestamp_id('statuses'::text)"))
}

@unique

Ensures field values are unique:

model User {
  id    Int    @id
  email String @unique
  slug  String @unique
}

Named unique constraint:

model User {
  id      Int    @id
  email   String @unique(map: "unique_user_email")
}

@relation

Defines relationships between models:

model Post {
  id       Int  @id
  authorId Int
  author   User @relation(fields: [authorId], references: [id])
}

model User {
  id    Int    @id
  posts Post[]
}

With referential actions:

model Post {
  id       Int  @id
  authorId Int
  author   User @relation(fields: [authorId], references: [id], onDelete: Cascade, onUpdate: NoAction)
}

Referential actions:

• Cascade - Delete/update related records
• NoAction - Prevent the operation
• SetNull - Set foreign key to null
• SetDefault - Set to default value
• Restrict - Prevent the operation (similar to NoAction)

Named relations (for multiple relations):

model User {
  id              Int              @id
  writtenPosts    Post[]           @relation("author")
  favoritePosts   Post[]           @relation("favorites")
}

model Post {
  id              Int    @id
  authorId        Int
  author          User   @relation("author", fields: [authorId], references: [id])
  favoritedBy     User[] @relation("favorites")
}

@map

Maps field name to different column name:

model User {
  id         Int    @id
  firstName  String @map("first_name")
  lastName   String @map("last_name")

  @@map("users")
}

@updatedAt

Automatically updates timestamp on record modification:

model Post {
  id        Int      @id
  title     String
  updatedAt DateTime @updatedAt
}

@db

Specifies native database type:

model Post {
  id      Int     @id
  title   String  @db.VarChar(255)
  content String  @db.Text
  price   Decimal @db.Decimal(10, 2)
  data    Bytes   @db.ByteA
}

Provider-specific types:

PostgreSQL:

model Example {
  id        Int      @id
  text      String   @db.Text
  varchar   String   @db.VarChar(255)
  uuid      String   @db.Uuid
  inet      String   @db.Inet
  citext    String   @db.Citext
  json      Json     @db.JsonB
  timestamp DateTime @db.Timestamptz
}

MySQL:

model Example {
  id       Int    @id
  text     String @db.Text
  longText String @db.LongText
  varchar  String @db.VarChar(255)
  tinyInt  Int    @db.TinyInt
}

SQL Server:

model Example {
  id       Int    @id
  nvarchar String @db.NVarChar(255)
  text     String @db.NVarChar(Max)
}

@ignore

Excludes field from Prisma Client:

model User {
  id       Int    @id
  email    String
  internal String @ignore
}

Model Attributes

@@id

Defines composite primary key:

model CourseEnrollment {
  userId   Int
  courseId Int
  role     String

  user   User   @relation(fields: [userId], references: [id])
  course Course @relation(fields: [courseId], references: [id])

  @@id([userId, courseId])
}

Named composite primary key:

model Assignment {
  courseId  Int
  studentId Int

  @@id([courseId, studentId], name: "assignment_id")
}

@@unique

Defines unique constraint on multiple fields:

model User {
  id        Int    @id
  firstName String
  lastName  String
  email     String

  @@unique([firstName, lastName])
  @@unique([email])
}

Named unique constraint:

model Post {
  id       Int    @id
  slug     String
  tenantId Int

  @@unique([slug, tenantId], map: "unique_slug_per_tenant")
}

@@index

Creates database index:

model Post {
  id       Int      @id
  title    String
  authorId Int
  status   String
  created  DateTime

  @@index([authorId])
  @@index([status, created])
}

Named index:

model User {
  id    Int    @id
  email String
  name  String

  @@index([email], map: "idx_user_email")
  @@index([name, email], map: "idx_user_name_email")
}

Index with sort order:

model Notification {
  id        Int      @id
  userId    Int
  createdAt DateTime

  @@index([userId, createdAt(sort: Desc)])
}

@@map

Maps model name to different table name:

model BlogPost {
  id    Int    @id
  title String

  @@map("blog_posts")
}

@@ignore

Excludes model from Prisma Client:

model InternalLog {
  id      Int    @id
  message String

  @@ignore
}

Useful for:

• Legacy tables not used in application
• Temporary migration tables
• Database views not managed by Prisma

Complete Examples

User Authentication

model User {
  id            Int       @id @default(autoincrement())
  email         String    @unique
  passwordHash  String    @map("password_hash")
  emailVerified Boolean   @default(false) @map("email_verified")
  createdAt     DateTime  @default(now()) @map("created_at")
  updatedAt     DateTime  @updatedAt @map("updated_at")
  lastLoginAt   DateTime? @map("last_login_at")

  sessions Session[]

  @@map("users")
}

model Session {
  id        String   @id @default(cuid())
  userId    Int      @map("user_id")
  token     String   @unique @db.VarChar(255)
  expiresAt DateTime @map("expires_at")
  createdAt DateTime @default(now()) @map("created_at")

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@index([userId])
  @@index([expiresAt])
  @@map("sessions")
}

E-commerce Products

model Product {
  id          Int      @id @default(autoincrement())
  sku         String   @unique @db.VarChar(50)
  name        String   @db.VarChar(255)
  description String?  @db.Text
  price       Decimal  @db.Decimal(10, 2)
  stock       Int      @default(0)
  active      Boolean  @default(true)
  createdAt   DateTime @default(now()) @map("created_at")
  updatedAt   DateTime @updatedAt @map("updated_at")

  @@index([sku])
  @@index([active, createdAt])
  @@map("products")
}

Social Media

model Post {
  id              Int      @id @default(autoincrement())
  content         String   @db.Text
  authorId        Int      @map("author_id")
  published       Boolean  @default(false)
  publishedAt     DateTime? @map("published_at")
  createdAt       DateTime @default(now()) @map("created_at")
  updatedAt       DateTime @updatedAt @map("updated_at")

  author   User      @relation(fields: [authorId], references: [id], onDelete: Cascade)
  comments Comment[]
  likes    Like[]

  @@index([authorId])
  @@index([published, publishedAt])
  @@map("posts")
}

model Like {
  userId    Int      @map("user_id")
  postId    Int      @map("post_id")
  createdAt DateTime @default(now()) @map("created_at")

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
  post Post @relation(fields: [postId], references: [id], onDelete: Cascade)

  @@id([userId, postId])
  @@map("likes")
}

Multi-tenant Application

model Tenant {
  id        Int      @id @default(autoincrement())
  slug      String   @unique @db.VarChar(50)
  name      String   @db.VarChar(255)
  createdAt DateTime @default(now()) @map("created_at")

  users User[]
  posts Post[]

  @@map("tenants")
}

model User {
  id       Int    @id @default(autoincrement())
  email    String @db.VarChar(255)
  tenantId Int    @map("tenant_id")

  tenant Tenant @relation(fields: [tenantId], references: [id])

  @@unique([email, tenantId])
  @@index([tenantId])
  @@map("users")
}

Best Practices

1. Always use @id or @@id for primary keys
2. Add @unique constraints for fields that should be unique
3. Use @default(autoincrement()) for auto-generated IDs
4. Include @default(now()) and @updatedAt for timestamps
5. Use @@map to match existing database naming conventions
6. Add @@index on foreign keys and frequently queried fields
7. Use named constraints with map: for better database management
8. Specify referential actions (onDelete, onUpdate) explicitly
9. Use @db attributes for database-specific optimizations
10. Consider composite keys with @@id for join tables