#Prisma with Next.js — The Production Setup¶

Prisma is the most popular ORM for Next.js. It gives you a type-safe query builder, schema migrations, and a great DX.

Install¶

bash

3 lines

1npm i @prisma/client
2npm i -D prisma
3npx prisma init

Choose Postgres in the prompts (most flexible).

A Real Schema¶

prisma

57 lines

1// prisma/schema.prisma
2generator client {
3  provider = "prisma-client-js"
4}
5
6datasource db {
7  provider = "postgresql"
8  url      = env("DATABASE_URL")
9}
10
11model User {
12  id           String   @id @default(cuid())
13  email        String   @unique
14  name         String?
15  passwordHash String
16  role         Role     @default(STUDENT)
17  createdAt    DateTime @default(now())
18
19  courses      Course[]
20  enrollments  Enrollment[]
21}
22
23enum Role { STUDENT INSTRUCTOR ADMIN }
24
25model Course {
26  id          String  @id @default(cuid())
27  slug        String  @unique
28  title       String
29  description String  @db.Text
30  createdById String
31
32  createdBy   User    @relation(fields: [createdById], references: [id])
33  lessons     Lesson[]
34  enrollments Enrollment[]
35}
36
37model Lesson {
38  id       String @id @default(cuid())
39  courseId String
40  title    String
41  content  String @db.Text
42  order    Int
43
44  course Course @relation(fields: [courseId], references: [id], onDelete: Cascade)
45}
46
47model Enrollment {
48  id        String   @id @default(cuid())
49  userId    String
50  courseId  String
51  createdAt DateTime @default(now())
52
53  user   User   @relation(fields: [userId], references: [id])
54  course Course @relation(fields: [courseId], references: [id])
55
56  @@unique([userId, courseId])
57}

The Singleton Client¶

In dev, hot-reload would create a new PrismaClient on every save → DB connection exhaustion.

11 lines

1// lib/db.ts
2import "server-only";
3import { PrismaClient } from "@prisma/client";
4
5const globalForPrisma = globalThis as unknown as { prisma?: PrismaClient };
6
7export const db =
8  globalForPrisma.prisma ??
9  new PrismaClient({ log: process.env.NODE_ENV === "development" ? ["query", "error"] : ["error"] });
10
11if (process.env.NODE_ENV !== "production") globalForPrisma.prisma = db;

Generating the Client¶

After every schema change:

bash

2 lines

1npx prisma generate            # regenerates the typed client
2npx prisma migrate dev --name <reason>   # applies a migration in dev

Add to package.json so it runs on install:

json

7 lines

1{
2  "scripts": {
3    "postinstall": "prisma generate",
4    "db:push":   "prisma db push",
5    "db:studio": "prisma studio"
6  }
7}

Migrations vs db push¶

Command	Use For
`prisma migrate dev`	Versioned migrations, committed to git
`prisma db push`	Quick prototyping, no migration files

Use migrate for any project that will reach production. Use db push for fast experimentation only.

Querying¶

18 lines

1// Find with relations
2const course = await db.course.findUnique({
3  where: { slug },
4  include: { lessons: { orderBy: { order: "asc" } } },
5});
6
7// Aggregate
8const stats = await db.enrollment.groupBy({
9  by: ["courseId"],
10  _count: { _all: true },
11  having: { courseId: { _count: { _all: { gt: 50 } } } },
12});
13
14// Transactions
15await db.$transaction(async (tx) => {
16  await tx.course.update({ where: { id }, data: { status: "PUBLISHED" } });
17  await tx.notification.create({ data: { /* … */ } });
18});

Connection Pooling¶

In serverless (Vercel), each invocation creates a fresh process. You must front Postgres with a pooler:

Neon has a built-in pooler — use the -pooler URL.
Supabase offers Supavisor.
PgBouncer for self-hosted.

For Prisma + serverless, also enable directUrl for migrations:

prisma

4 lines

1datasource db {
2  url      = env("DATABASE_URL")        // pooled, used at runtime
3  directUrl = env("DIRECT_URL")          // direct, used only for migrations
4}