Configuration

Mevn ORM must be configured once before any Model method runs. Use configureDb0(useDatabase()) for Nitro's existing db0 connection. Use configureDatabase for a direct Knex connection, or configure when you already have a Knex config or instance.

Nitro db0 connection

import { configureDb0 } from 'mevn-orm/db0'

export default defineNitroPlugin(() => {
  configureDb0(useDatabase())
})

Configure the connection with Nitro's database option. Mevn ORM supports db0 SQLite and MySQL here; Knex builds the queries while db0 executes them. See Nuxt / Nitro for the connection and migration examples.

configureDatabase (direct Knex)

import { configureDatabase } from 'mevn-orm'

configureDatabase({
  client: 'better-sqlite3',
  connection: {
    filename: './dev.sqlite'
  }
})

Supported clients

Input client	Knex driver used
better-sqlite3	better-sqlite3 (preferred SQLite)
sqlite3, sqlite	better-sqlite3 (aliases on this helper only)
mysql2, mysql	mysql2
pg, postgres, postgresql	pg
pgnative, cockroachdb, redshift	as named / via pg family
mssql	mssql
oracledb, oracle	oracledb

A deprecated dialect field is still accepted for backwards compatibility. Prefer client.

SQLite aliases (sqlite3, sqlite) only apply here and in createKnexConfig. They still require the better-sqlite3 package. Passing client: 'sqlite3' to configure() is not remapped and uses Knex’s sqlite3 driver instead.

Connection styles

Connection object

configureDatabase({
  client: 'mysql2',
  connection: {
    host: '127.0.0.1',
    port: 3306,
    user: 'root',
    password: 'secret',
    database: 'app_db'
  }
})

Connection string

configureDatabase({
  client: 'pg',
  connection: process.env.DATABASE_URL
})

// or via connectionString
configureDatabase({
  client: 'pg',
  connectionString: process.env.DATABASE_URL
})

SQLite file

configureDatabase({
  client: 'better-sqlite3',
  connection: {
    filename: './dev.sqlite'
  }
})

// top-level filename also works
configureDatabase({
  client: 'better-sqlite3',
  filename: './dev.sqlite'
})

Top-level host fields

configureDatabase({
  client: 'mysql2',
  host: '127.0.0.1',
  port: 3306,
  user: 'root',
  password: 'secret',
  database: 'app_db'
})

MSSQL

configureDatabase({
  client: 'mssql',
  connection: {
    host: '127.0.0.1',
    user: 'sa',
    password: 'StrongPassword!',
    database: 'app_db',
    // MSSQL driver options live under `options` (passed through to tedious)
    options: {
      encrypt: true
    }
  }
})

Pool and debug

configureDatabase({
  client: 'pg',
  connection: process.env.DATABASE_URL,
  pool: {
    min: 2,
    max: 10
  },
  debug: process.env.NODE_ENV !== 'production'
})

SQLite configs automatically set useNullAsDefault: true for Knex.

createKnexConfig

Build a Knex config without initialising the global client (useful for tests or dual connections):

import { createKnexConfig, configure } from 'mevn-orm'
import knex from 'knex'

const config = createKnexConfig({
  client: 'better-sqlite3',
  connection: { filename: ':memory:' }
})

// Inspect or merge, then configure
configure(config)

// Or use Knex yourself
const db = knex(config)

configure (advanced)

Pass a full Knex config or an existing Knex instance:

import knex from 'knex'
import { configure } from 'mevn-orm'

// Full Knex config
configure({
  client: 'pg',
  connection: process.env.DATABASE_URL,
  searchPath: ['knex', 'public'],
  pool: { min: 0, max: 7 }
})

// Existing instance
const db = knex({ client: 'better-sqlite3', connection: { filename: './dev.sqlite' }, useNullAsDefault: true })
configure(db)

Accessing Knex

import { DB, getDB } from 'mevn-orm'

// After configure / configureDatabase:
const users = await getDB()('users').select('*')

// DB is the same instance once configured (see package export notes)

getDB() throws if the ORM has not been configured yet:

Mevn ORM is not configured. Call configure({ client, connection, ... }) before using Model.

Environment-based setup

// src/db.ts
import { configureDatabase } from 'mevn-orm'

export function initDatabase() {
  const client = (process.env.DB_CLIENT ?? 'better-sqlite3') as 'better-sqlite3' | 'mysql2' | 'pg'

  if (client === 'better-sqlite3') {
    configureDatabase({
      client,
      connection: { filename: process.env.DB_FILENAME ?? './dev.sqlite' }
    })
    return
  }

  if (process.env.DATABASE_URL) {
    configureDatabase({
      client,
      connection: process.env.DATABASE_URL
    })
    return
  }

  configureDatabase({
    client,
    connection: {
      host: process.env.DB_HOST,
      port: Number(process.env.DB_PORT),
      user: process.env.DB_USER,
      password: process.env.DB_PASSWORD,
      database: process.env.DB_NAME
    }
  })
}

Example env file

# .env.example
DB_CLIENT=mysql2
DB_HOST=127.0.0.1
DB_PORT=3306
DB_USER=root
DB_PASSWORD=
DB_NAME=app_db

# Or use a URL
# DATABASE_URL=postgres://user:pass@localhost:5432/app_db

Next steps

• Models
• Migrations
• Raw Knex
• Nuxt / Nitro