/prisma-orm-setup

MySQL Setup

Configure Prisma ORM 7 with MySQL and MariaDB. For an existing Prisma 6 app, keep its configuration and use the Prisma 6 docs; the configuration and adapter examples below are for 7.

Prerequisites

• MySQL or MariaDB database
• Connection string

1. Schema Configuration

In prisma/schema.prisma:

datasource db {
  provider = "mysql"
}

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

2. Config Configuration

In prisma.config.ts:

import 'dotenv/config'
import { defineConfig, env } from 'prisma/config'

export default defineConfig({
  schema: 'prisma/schema.prisma',
  datasource: {
    url: env('DATABASE_URL'),
  },
})

3. Environment Variable

In .env:

DATABASE_URL="mysql://user:password@localhost:3306/mydb"

Connection String Format

mysql://USER:PASSWORD@HOST:PORT/DATABASE

• USER: Database user
• PASSWORD: Password
• HOST: Hostname
• PORT: Port (default 3306)
• DATABASE: Database name

Driver Adapter

Use a driver adapter for the standard SQL workflow.

1. Install adapter and driver:

   npm install @prisma/adapter-mariadb@7 mariadb

2. Set MYSQL_USER, MYSQL_PASSWORD, and MYSQL_DATABASE in the application environment to match the CLI URL, and use the same host and port. Instantiate Prisma Client with the adapter:

   import 'dotenv/config'
   import { PrismaClient } from '../generated/client'
   import { PrismaMariaDb } from '@prisma/adapter-mariadb'
   
   const adapter = new PrismaMariaDb({
     host: 'localhost',
     port: 3306,
     connectionLimit: 5,
     user: process.env.MYSQL_USER,
     password: process.env.MYSQL_PASSWORD,
     database: process.env.MYSQL_DATABASE,
   })
   
   const prisma = new PrismaClient({ adapter })

Text protocol option

If you need the MariaDB driver's text protocol instead of the default binary execute() path, enable useTextProtocol explicitly:

import { PrismaClient } from '../generated/client'
import { PrismaMariaDb } from '@prisma/adapter-mariadb'

const adapter = new PrismaMariaDb(process.env.DATABASE_URL!, {
  useTextProtocol: true,
})

const prisma = new PrismaClient({ adapter })

Use this only when you specifically need text-protocol compatibility for your MariaDB setup.

PlanetScale Setup

Check whether foreign key constraints are enabled on the PlanetScale database. When they are disabled, use relationMode = "prisma" and add indexes for relation fields. Do not override an existing database that has foreign keys enabled.

In prisma/schema.prisma:

datasource db {
  provider     = "mysql"
  relationMode = "prisma" // Emulate foreign keys in Prisma
}

Common Issues

"Too many connections"

Set connectionLimit on PrismaMariaDb, as in the example above. The Prisma 6 connection_limit URL parameter does not configure the Prisma 7 adapter pool.

JSON Support

MySQL 5.7+ supports JSON. MariaDB 10.2+ supports JSON (as an alias for LONGTEXT with check constraints). Prisma handles this, but verify your version.

References

• Prisma 7 connection pool settings
• PlanetScale foreign key configuration
• Prisma 7 MySQL and MariaDB documentation