---
layout: page
title: Express database integration
description: Discover how to integrate various databases with Express.js applications, including setup examples for MongoDB, MySQL, PostgreSQL, and more.
menu: guide
order: 11
redirect_from: "/guide/database-integration.html"
---

# Database integration

Adding the capability to connect databases to Express apps is just a matter of loading an appropriate Node.js driver for the database in your app. This document briefly explains how to add and use some of the most popular Node.js modules for database systems in your Express app:

* [Cassandra](#cassandra)
* [Couchbase](#couchbase)
* [CouchDB](#couchdb)
* [LevelDB](#leveldb)
* [MySQL](#mysql)
* [MongoDB](#mongodb)
* [Neo4j](#neo4j)
* [Oracle](#oracle)
* [PostgreSQL](#postgresql)
* [Redis](#redis)
* [SQL Server](#sql-server)
* [SQLite](#sqlite)
* [Elasticsearch](#elasticsearch)

<div class="doc-box doc-notice" markdown="1">
These database drivers are among many that are available. For other options,
search on the [npm](https://www.npmjs.com/) site.
</div>

## Cassandra

**Module**: [cassandra-driver](https://github.com/datastax/nodejs-driver)

### Installation

```bash
$ npm install cassandra-driver
```

### Example

```js
const cassandra = require('cassandra-driver')
const client = new cassandra.Client({ contactPoints: ['localhost'] })

client.execute('select key from system.local', (err, result) => {
  if (err) throw err
  console.log(result.rows[0])
})
```

## Couchbase

**Module**: [couchnode](https://github.com/couchbase/couchnode)

### Installation

```bash
$ npm install couchbase
```

### Example

```js
const couchbase = require('couchbase')
const bucket = (new couchbase.Cluster('http://localhost:8091')).openBucket('bucketName')

// add a document to a bucket
bucket.insert('document-key', { name: 'Matt', shoeSize: 13 }, (err, result) => {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})

// get all documents with shoe size 13
const n1ql = 'SELECT d.* FROM `bucketName` d WHERE shoeSize = $1'
const query = N1qlQuery.fromString(n1ql)
bucket.query(query, [13], (err, result) => {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})
```

## CouchDB

**Module**: [nano](https://github.com/dscape/nano)

### Installation

```bash
$ npm install nano
```

### Example

```js
const nano = require('nano')('http://localhost:5984')
nano.db.create('books')
const books = nano.db.use('books')

// Insert a book document in the books database
books.insert({ name: 'The Art of war' }, null, (err, body) => {
  if (err) {
    console.log(err)
  } else {
    console.log(body)
  }
})

// Get a list of all books
books.list((err, body) => {
  if (err) {
    console.log(err)
  } else {
    console.log(body.rows)
  }
})
```

## LevelDB

**Module**: [levelup](https://github.com/rvagg/node-levelup)

### Installation

```bash
$ npm install level levelup leveldown
```

### Example

```js
const levelup = require('levelup')
const db = levelup('./mydb')

db.put('name', 'LevelUP', (err) => {
  if (err) return console.log('Ooops!', err)

  db.get('name', (err, value) => {
    if (err) return console.log('Ooops!', err)

    console.log(`name=${value}`)
  })
})
```

## MySQL

**Module**: [mysql](https://github.com/felixge/node-mysql/)

### Installation

```bash
$ npm install mysql
```

### Example

```js
const mysql = require('mysql')
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'dbuser',
  password: 's3kreee7',
  database: 'my_db'
})

connection.connect()

connection.query('SELECT 1 + 1 AS solution', (err, rows, fields) => {
  if (err) throw err

  console.log('The solution is: ', rows[0].solution)
})

connection.end()
```

## MongoDB

**Module**: [mongodb](https://github.com/mongodb/node-mongodb-native)

### Installation

```bash
$ npm install mongodb
```

### Example (v2.*)

```js
const MongoClient = require('mongodb').MongoClient

MongoClient.connect('mongodb://localhost:27017/animals', (err, db) => {
  if (err) throw err

  db.collection('mammals').find().toArray((err, result) => {
    if (err) throw err

    console.log(result)
  })
})
```

### Example (v3.*)

```js
const MongoClient = require('mongodb').MongoClient

MongoClient.connect('mongodb://localhost:27017/animals', (err, client) => {
  if (err) throw err

  const db = client.db('animals')

  db.collection('mammals').find().toArray((err, result) => {
    if (err) throw err

    console.log(result)
  })
})
```


If you want an object model driver for MongoDB, look at [Mongoose](https://github.com/LearnBoost/mongoose).

## Neo4j

**Module**: [neo4j-driver](https://github.com/neo4j/neo4j-javascript-driver)

### Installation

```bash
$ npm install neo4j-driver
```

### Example

```js
const neo4j = require('neo4j-driver')
const driver = neo4j.driver('neo4j://localhost:7687', neo4j.auth.basic('neo4j', 'letmein'))

const session = driver.session()

session.readTransaction((tx) => {
  return tx.run('MATCH (n) RETURN count(n) AS count')
    .then((res) => {
      console.log(res.records[0].get('count'))
    })
    .catch((error) => {
      console.log(error)
    })
})
```

## Oracle

**Module**: [oracledb](https://github.com/oracle/node-oracledb)

### Installation

 NOTE: [See installation prerequisites](https://github.com/oracle/node-oracledb#-installation).

```bash
$ npm install oracledb
```

### Example

```js
const oracledb = require('oracledb')
const config = {
  user: '<your db user>',
  password: '<your db password>',
  connectString: 'localhost:1521/orcl'
}

async function getEmployee (empId) {
  let conn

  try {
    conn = await oracledb.getConnection(config)

    const result = await conn.execute(
      'select * from employees where employee_id = :id',
      [empId]
    )

    console.log(result.rows[0])
  } catch (err) {
    console.log('Ouch!', err)
  } finally {
    if (conn) { // conn assignment worked, need to close
      await conn.close()
    }
  }
}

getEmployee(101)
```

## PostgreSQL

**Module**: [pg-promise](https://github.com/vitaly-t/pg-promise)

### Installation

```bash
$ npm install pg-promise
```

### Example

```js
const pgp = require('pg-promise')(/* options */)
const db = pgp('postgres://username:password@host:port/database')

db.one('SELECT $1 AS value', 123)
  .then((data) => {
    console.log('DATA:', data.value)
  })
  .catch((error) => {
    console.log('ERROR:', error)
  })
```

## Redis

**Module**: [redis](https://github.com/mranney/node_redis)

### Installation

```bash
$ npm install redis
```

### Example

```js
const redis = require('redis')
const client = redis.createClient()

client.on('error', (err) => {
  console.log(`Error ${err}`)
})

client.set('string key', 'string val', redis.print)
client.hset('hash key', 'hashtest 1', 'some value', redis.print)
client.hset(['hash key', 'hashtest 2', 'some other value'], redis.print)

client.hkeys('hash key', (err, replies) => {
  console.log(`${replies.length} replies:`)

  replies.forEach((reply, i) => {
    console.log(`    ${i}: ${reply}`)
  })

  client.quit()
})
```

## SQL Server

**Module**: [tedious](https://github.com/tediousjs/tedious)

### Installation

```bash
$ npm install tedious
```

### Example

```js
const Connection = require('tedious').Connection
const Request = require('tedious').Request

const config = {
  server: 'localhost',
  authentication: {
    type: 'default',
    options: {
      userName: 'your_username', // update me
      password: 'your_password' // update me
    }
  }
}

const connection = new Connection(config)

connection.on('connect', (err) => {
  if (err) {
    console.log(err)
  } else {
    executeStatement()
  }
})

function executeStatement () {
  request = new Request("select 123, 'hello world'", (err, rowCount) => {
    if (err) {
      console.log(err)
    } else {
      console.log(`${rowCount} rows`)
    }
    connection.close()
  })

  request.on('row', (columns) => {
    columns.forEach((column) => {
      if (column.value === null) {
        console.log('NULL')
      } else {
        console.log(column.value)
      }
    })
  })

  connection.execSql(request)
}
```

## SQLite

**Module**: [sqlite3](https://github.com/mapbox/node-sqlite3)

### Installation

```bash
$ npm install sqlite3
```

### Example

```js
const sqlite3 = require('sqlite3').verbose()
const db = new sqlite3.Database(':memory:')

db.serialize(() => {
  db.run('CREATE TABLE lorem (info TEXT)')
  const stmt = db.prepare('INSERT INTO lorem VALUES (?)')

  for (let i = 0; i < 10; i++) {
    stmt.run(`Ipsum ${i}`)
  }

  stmt.finalize()

  db.each('SELECT rowid AS id, info FROM lorem', (err, row) => {
    console.log(`${row.id}: ${row.info}`)
  })
})

db.close()
```

## Elasticsearch

**Module**: [elasticsearch](https://github.com/elastic/elasticsearch-js)

### Installation

```bash
$ npm install elasticsearch
```

### Example

```js
const elasticsearch = require('elasticsearch')
const client = elasticsearch.Client({
  host: 'localhost:9200'
})

client.search({
  index: 'books',
  type: 'book',
  body: {
    query: {
      multi_match: {
        query: 'express js',
        fields: ['title', 'description']
      }
    }
  }
}).then((response) => {
  const hits = response.hits.hits
}, (error) => {
  console.trace(error.message)
})
```