PlanetScale

PlanetScale is a serverless database platform. This guide covers both PlanetScale MySQL and PlanetScale Postgres. In this guide, you will learn how to add Prisma ORM to an existing TypeScript project, connect it to PlanetScale, introspect your existing database schema, and start querying with type-safe Prisma Client.

Prerequisites

1. Set up Prisma ORM

Navigate to your existing project directory and install the required dependencies:

MySQL

npm install prisma @types/node --save-dev
npm install @prisma/client @prisma/adapter-planetscale undici dotenv

Postgres

npm install prisma @types/node @types/pg --save-dev
npm install @prisma/client @prisma/adapter-pg pg dotenv

2. Initialize Prisma ORM

Set up your Prisma ORM project by creating your Prisma Schema file with the following command:

MySQL

npx prisma init --datasource-provider mysql --output ../generated/prisma

Postgres

npx prisma init --datasource-provider postgresql --output ../generated/prisma

This command does a few things:

• Creates a prisma/ directory with a schema.prisma file containing your database connection configuration
• Creates a .env file in the root directory for environment variables
• Creates a prisma.config.ts file for Prisma configuration

The generated prisma.config.ts file looks 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 generated schema uses the ESM-first prisma-client generator with a custom output path:

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

datasource db {
  provider     = "mysql"
  relationMode = "prisma"
}

3. Connect your database

Update the .env file with your PlanetScale connection URL:

DATABASE_URL="mysql://username:password@host.connect.psdb.cloud/mydb?sslaccept=strict"

You can find your connection string in the PlanetScale dashboard.

4. Introspect your database

Run the following command to introspect your existing database:

npx prisma db pull

This command reads the DATABASE_URL environment variable, connects to your database, and introspects the database schema. It then translates the database schema from SQL into a data model in your Prisma schema.

After introspection, your Prisma schema will contain models that represent your existing database tables.

5. Generate Prisma ORM types

Generate Prisma Client based on your introspected schema:

npx prisma generate

This creates a type-safe Prisma Client tailored to your database schema in the generated/prisma directory.

6. Instantiate Prisma Client

Create a utility file to instantiate Prisma Client. You need to pass an instance of the Prisma ORM driver adapter adapter to the PrismaClient constructor:

import "dotenv/config";
import { PrismaPlanetScale } from "@prisma/adapter-planetscale";
import { PrismaClient } from "../generated/prisma/client";
import { fetch as undiciFetch } from "undici";

const adapter = new PrismaPlanetScale({ url: process.env.DATABASE_URL, fetch: undiciFetch });
const prisma = new PrismaClient({ adapter });

export { prisma };

7. Query your database

Now you can use Prisma Client to query your database. Create a script.ts file:

import { prisma } from "./lib/prisma";

async function main() {
  // Example: Fetch all records from a table
  // Replace 'user' with your actual model name
  const allUsers = await prisma.user.findMany();
  console.log("All users:", JSON.stringify(allUsers, null, 2));
}

main()
  .then(async () => {
    await prisma.$disconnect();
  })
  .catch(async (e) => {
    console.error(e);
    await prisma.$disconnect();
    process.exit(1);
  });

Run the script:

npx tsx script.ts

8. Evolve your schema

PlanetScale uses a branching workflow instead of traditional migrations. To make changes to your database schema:

8.1. Update your Prisma schema file

Update your Prisma schema file to reflect the changes you want to make to your database schema. For example, add a new model:

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

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

8.2. Push the changes to your development branch:

npx prisma db push

This command will:

• Apply the schema changes to your PlanetScale database
• Regenerate Prisma Client

9. Explore your data with Prisma Studio

npx prisma studio

Next steps

You've successfully set up Prisma ORM. Here's what you can explore next:

• Learn more about Prisma Client: Explore the Prisma Client API for advanced querying, filtering, and relations
• Database migrations: Learn about Prisma Migrate for evolving your database schema
• Performance optimization: Discover query optimization techniques
• Build a full application: Check out our framework guides to integrate Prisma ORM with Next.js, Express, and more
• Join the community: Connect with other developers on Discord

More info

• PlanetScale database connector
• Prisma Config reference
• Database introspection
• PlanetScale branching workflow