MySQL Setup

Configure Prisma with MySQL (or MariaDB).

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 { 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.

Install adapter and driver:

npm install @prisma/adapter-mariadb mariadb

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

PlanetScale uses MySQL but requires specific settings because it doesn't support foreign key constraints.

In prisma/schema.prisma:

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

Common Issues

"Too many connections"

MySQL has a connection limit. Adjust connection pool size in URL:

DATABASE_URL="mysql://...?connection_limit=5"

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.

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