Prisma ORM - Type-Safe Database Toolkit

Modern database toolkit for TypeScript with schema-first development, auto-generated type-safe client, and powerful migration system.

Quick Reference

Installation

npm install prisma @prisma/client
npx prisma init

Basic Workflow

# 1. Define schema
# Edit prisma/schema.prisma

# 2. Create migration
npx prisma migrate dev --name init

# 3. Generate client
npx prisma generate

# 4. Open Studio
npx prisma studio

Core Schema Pattern

// prisma/schema.prisma
generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model User {
  id        String   @id @default(cuid())
  email     String   @unique
  name      String?
  posts     Post[]
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

model Post {
  id        String   @id @default(cuid())
  title     String
  content   String?
  published Boolean  @default(false)
  author    User     @relation(fields: [authorId], references: [id])
  authorId  String
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt

  @@index([authorId])
}

Type-Safe CRUD

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

// Create
const user = await prisma.user.create({
  data: {
    email: '[email protected]',
    name: 'Alice',
    posts: {
      create: { title: 'First Post', content: 'Hello World' }
    }
  },
  include: { posts: true }
});

// Read with filters
const users = await prisma.user.findMany({
  where: { email: { contains: '@example.com' } },
  include: { posts: { where: { published: true } } },
  orderBy: { createdAt: 'desc' },
  take: 10
});

// Update
await prisma.user.update({
  where: { id: userId },
  data: { name: 'Bob' }
});

// Delete
await prisma.user.delete({ where: { id: userId } });

Schema Design Patterns

Field Types and Attributes

model Product {
  id          Int      @id @default(autoincrement())
  sku         String   @unique
  name        String
  description String?  // Optional field
  price       Decimal  @db.Decimal(10, 2)
  inStock     Boolean  @default(true)
  quantity    Int      @default(0)
  tags        String[] // Array field (PostgreSQL)
  metadata    Json?    // JSON field
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt

  @@index([sku])
  @@index([name, inStock])
}

Relations

One-to-Many:

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

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

  @@index([authorId])
}

Many-to-Many:

model Post {
  id         String     @id @default(cuid())
  categories Category[] @relation("PostCategories")
}

model Category {
  id    String @id @default(cuid())
  name  String @unique
  posts Post[] @relation("PostCategories")
}

One-to-One:

model User {
  id      String   @id @default(cuid())
  profile Profile?
}

model Profile {
  id     String @id @default(cuid())
  bio    String
  user   User   @relation(fields: [userId], references: [id])
  userId String @unique
}

Self-Relations:

model User {
  id        String @id @default(cuid())
  following User[] @relation("UserFollows")
  followers User[] @relation("UserFollows")
}

Client Operations

Nested Writes

// Create with nested relations
const user = await prisma.user.create({
  data: {
    email: '[email protected]',
    profile: {
      create: { bio: 'Software Engineer' }
    },
    posts: {
      create: [
        { title: 'Post 1', content: 'Content 1' },
        { title: 'Post 2', content: 'Content 2' }
      ]
    }
  }
});

// Update with nested operations
await prisma.user.update({
  where: { id: userId },
  data: {
    posts: {
      create: { title: 'New Post' },
      update: {
        where: { id: postId },
        data: { published: true }
      },
      delete: { id: oldPostId }
    }
  }
});

Transactions

Sequential (Interactive):

await prisma.$transaction(async (tx) => {
  const user = await tx.user.create({
    data: { email: '[email protected]' }
  });

  await tx.post.create({
    data: { title: 'Post', authorId: user.id }
  });

  // Rollback if error thrown
  if (someCondition) {
    throw new Error('Rollback transaction');
  }
});

Batch (Parallel):

const [deletedPosts, updatedUser] = await prisma.$transaction([
  prisma.post.deleteMany({ where: { published: false } }),
  prisma.user.update({
    where: { id: userId },
    data: { name: 'Updated' }
  })
]);

Advanced Queries

Aggregations:

const result = await prisma.post