Prisma ORM

Type-safe database access with auto-generated queries.

Quick Start

// schema.prisma
model User {
  id    Int     @id @default(autoincrement())
  email String  @unique
  name  String?
  posts Post[]
}

model Post {
  id        Int      @id @default(autoincrement())
  title     String
  content   String?
  author    User     @relation(fields: [authorId], references: [id])
  authorId  Int
}

import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();

// Type-safe query
const user = await prisma.user.create({
  data: {
    email: 'alice@example.com',
    posts: { create: { title: 'Hello Prisma' } }
  },
  include: { posts: true }
});

When to Use

• Type-safe database access
• Rapid schema evolution with migrations
• Not for complex raw SQL queries

Best Practices

• Define the schema as the single source of truth; generate the client.
• Use migrations for every schema change, committed with the code.
• Select only needed fields (`select`) to avoid over-fetching.
• Use `include`/`relationLoadStrategy` deliberately to prevent N+1.
• Batch writes with `createMany`/`updateMany`.
• Use transactions for multi-step consistency.

Step-by-Step Instructions

1. Install: `npm install prisma @prisma/client`

2. Init: `npx prisma init`

3. Define models in `schema.prisma`

4. Migrate: `npx prisma migrate dev`

5. Generate client and query with types

Dependencies

npm install prisma @prisma/client
npx prisma init

Examples

Input: `prisma.user.findMany({ where: { email: { contains: "@" } } })` → Output: All users with @ in email

// Paginated, type-safe query with relations
const page = await prisma.user.findMany({
  where: { role: "member" },
  select: { id: true, email: true, posts: { select: { title: true } } },
  orderBy: { id: "desc" },
  take: 20,
  skip: 40,
});

// Transaction for consistency
await prisma.$transaction([
  prisma.order.create({ data: { userId, amount } }),
  prisma.user.update({ where: { id: userId }, data: { balance: { decrement: amount } } }),
]);

Resources

• [Prisma Docs](https://www.prisma.io/docs)
• [Examples](./examples/)

Troubleshooting

• **`PrismaClientInitializationError`** — the schema is out of sync.

Re-run `npx prisma generate` and check the `DATABASE_URL` is reachable.

• **Introspection overwrites custom types** — treat `prisma db pull` as

an initial scaffold; re-apply manual types and relations afterwards.

• **Relation queries are slow** — missing index. Add `@@index` on foreign

keys and use the Prisma Data Platform for query analysis.

• **Migrations drift on team branches** — run `prisma migrate dev` early

and often; rebase migrations instead of resetting the database.

Validation

1. Schema validates: `npx prisma validate`

2. Migration applies successfully

3. Generated client is type-safe