Turborepo

Prisma is a powerful ORM for managing databases, and Turborepo simplifies monorepo workflows. By combining these tools, you can create a scalable, modular architecture for your projects.

This guide will show you how to set up Prisma as a standalone package in a Turborepo monorepo, enabling efficient configuration, type sharing, and database management across multiple apps.

What you'll learn:

• How to set up Prisma in a Turborepo monorepo.
• Steps to generate and reuse PrismaClient across packages.
• Integrating the Prisma package into other applications in the monorepo.

Prerequisites

• Node.js 20+

1. Set up your project

To set up a Turborepo monorepo named turborepo-prisma, run the following command:

npx create-turbo@latest turborepo-prisma

You'll be prompted to select your package manager, this guide will use npm:

After the setup, choose a package manager for the project. Navigate to the project root directory and install Turborepo as a development dependency:

cd turborepo-prisma
npm install turbo --save-dev

For more information about installing Turborepo, refer to the official Turborepo guide.

2. Add a new database package to the monorepo

2.1 Create the package and install Prisma

Create a database package within the packages directory. Then, create a package.json file for the package by running:

cd packages/
mkdir database
cd database
touch package.json

Define the package.json file as follows:

{
  "name": "@repo/db",
  "version": "0.0.0"
}

Next, install the required dependencies to use Prisma ORM. Use your preferred package manager:

npm install prisma @types/pg --save-dev

npm install @prisma/client @prisma/adapter-pg dotenv pg

yarn add prisma @types/pg --dev
yarn add @prisma/client @prisma/adapter-pg dotenv pg

2.2. Initialize Prisma and define models

Inside the database directory, initialize prisma by running:

npx prisma init --db --output ../generated/prisma

This will create several files inside packages/database:

• A prisma directory with a schema.prisma file.
• A prisma.config.ts file for configuring Prisma
• A Prisma Postgres database.
• A .env file containing the DATABASE_URL at the project root.
• An output directory for the generated Prisma Client as generated/prisma.

In the packages/database/prisma/schema.prisma file, add the following models:

generator client {
  provider = "prisma-client"
  output   = "../generated/prisma"
}

datasource db {
  provider = "postgresql"
}

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?
  published Boolean @default(false) 
  authorId  Int
  author    User    @relation(fields: [authorId], references: [id]) 
} 

The prisma.config.ts file created in the packages/database directory should look like this:

import "dotenv/config";
import { defineConfig, env } from "prisma/config";

export default defineConfig({
  schema: "prisma/schema.prisma",
  migrations: {
    path: "prisma/migrations",
  },
  datasource: {
    url: env("DATABASE_URL"),
  },
});

The importance of generating Prisma types in a custom directory

In the schema.prisma file, we specify a custom output path where Prisma will generate its types. This ensures Prisma's types are resolved correctly across different package managers.

2.3. Add scripts and run migrations

Let's add some scripts to the package.json inside packages/database:

{
  "name": "@repo/db",
  "version": "0.0.0",
  "scripts": {
    "db:generate": "prisma generate", 
    "db:migrate": "prisma migrate dev --skip-generate", 
    "db:deploy": "prisma migrate deploy"
  }, 
  "devDependencies": {
    "prisma": "^6.6.0"
  },
  "dependencies": {
    "@prisma/client": "^6.6.0"
  }
}

Let's also add these scripts to turbo.json in the root and ensure that DATABASE_URL is added to the environment:

{
"$schema": "https://turbo.build/schema.json",
"ui": "tui",
"tasks": {
  "build": {
    "dependsOn": ["^build"],
    "inputs": ["$TURBO_DEFAULT$", ".env*"],
    "outputs": [".next/**", "!.next/cache/**"],
    "env": ["DATABASE_URL"] 
  },
  "lint": {
    "dependsOn": ["^lint"]
  },
  "check-types": {
    "dependsOn": ["^check-types"]
  },
  "dev": {
    "cache": false,
    "persistent": true
  },
  "db:generate": { 
    "cache": false
  }, 
  "db:migrate": { 
    "cache": false, 
    "persistent": true // This is necessary to interact with the CLI and assign names to your database migrations.
  }, 
  "db:deploy": { 
    "cache": false
  } 
}

Migrate your prisma.schema and generate types

Navigate to the project root and run the following command to automatically migrate our database:

npx turbo db:migrate

Generate your schema.prisma

To generate the types from Prisma schema, from the project root run:

npx turbo db:generate

2.4. Export the Prisma client and types

Next, export the generated types and an instance of PrismaClient so it can used in your applications.

In the packages/database directory, create a src folder and add a client.ts file. This file will define an instance of PrismaClient:

import { PrismaClient } from "../generated/prisma/client";
import { PrismaPg } from "@prisma/adapter-pg";

const adapter = new PrismaPg({
  connectionString: process.env.DATABASE_URL,
});

const globalForPrisma = global as unknown as { prisma: PrismaClient };

export const prisma =
  globalForPrisma.prisma ||
  new PrismaClient({
    adapter,
  });

if (process.env.NODE_ENV !== "production") globalForPrisma.prisma = prisma;

Then create an index.ts file in the src folder to re-export the generated prisma types and the PrismaClient instance:

export { prisma } from "./client"; // exports instance of prisma
export * from "../generated/prisma/client"; // exports generated types from prisma

Follow the Just-in-Time packaging pattern and create an entrypoint to the package inside packages/database/package.json:

{
  "name": "@repo/db",
  "version": "0.0.0",
  "scripts": {
    "db:generate": "npx prisma generate",
    "db:migrate": "npx prisma migrate dev --skip-generate",
    "db:deploy": "npx prisma migrate deploy"
  },
  "devDependencies": {
    "prisma": "^6.6.0"
  },
  "dependencies": {
    "@prisma/client": "^6.6.0"
  },
  "exports": {
    ".": "./src/index.ts"
  } 
}

By completing these steps, you'll make the Prisma types and PrismaClient instance accessible throughout the monorepo.

3. Import the database package in the web app

The turborepo-prisma project should have an app called web at apps/web. Add the database dependency to apps/web/package.json:

{
  // ...
  "dependencies": {
    "@repo/db": "*"
    // ...
  }
  // ...
}

Run your package manager's install command inside the apps/web directory:

cd apps/web
npm install

Let's import the instantiated prisma client from the database package in the web app.

In the apps/web/app directory, open the page.tsx file and add the following code:

import styles from "./page.module.css";
import { prisma } from "@repo/db";

export default async function Home() {
  const user = await prisma.user.findFirst();
  return <div className={styles.page}>{user?.name ?? "No user added yet"}</div>;
}

Then, create a .env file in the web directory and copy into it the contents of the .env file from the /database directory containing the DATABASE_URL:

DATABASE_URL="Same database url as used in the database directory" # [!code ++]

4. Configure task dependencies in Turborepo

The db:generate and db:deploy scripts are not yet optimized for the monorepo setup but are essential for the dev and build tasks.

If a new developer runs turbo dev on an application without first running db:generate, they will encounter errors.

To prevent this, ensure that db:generate is always executed before running dev or build. Additionally, make sure both db:deploy and db:generate are executed before db:build. Here's how to configure this in your turbo.json file:

{
  "$schema": "https://turbo.build/schema.json",
  "ui": "tui",
  "tasks": {
    "build": {
      "dependsOn": ["^build", "^db:generate"], 
      "inputs": ["$TURBO_DEFAULT$", ".env*"],
      "outputs": [".next/**", "!.next/cache/**"],
      "env": ["DATABASE_URL"] 
    },
    "lint": {
      "dependsOn": ["^lint"]
    },
    "check-types": {
      "dependsOn": ["^check-types"]
    },
    "dev": {
      "dependsOn": ["^db:generate"], 
      "cache": false,
      "persistent": true
    },
    "db:generate": {
      "cache": false
    },
    "db:migrate": {
      "cache": false,
      "persistent": true
    },
    "db:deploy": {
      "cache": false
    }
  }
}

5. Run the project in development

"script":{
    "dev": "next dev --port 3000", 
}

Then from the project root run the project:

npx turbo run dev --filter=web

Navigate to the http://localhost:3000 and you should see the message:

No user added yet

npx prisma studio

Congratulations, you're done setting up Prisma for Turborepo!

Next Steps

• Expand your Prisma models to handle more complex data relationships.
• Implement additional CRUD operations to enhance your application's functionality.
• Check out Prisma Postgres to see how you can scale your application.

More Info

• Turborepo Docs
• Next.js Docs
• Prisma ORM Docs