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
• Couchbase
• CouchDB
• LevelDB
• MySQL
• MongoDB
• Neo4j
• PostgreSQL
• Redis
• SQL Server
• SQLite
• ElasticSearch

Cassandra

Module: cassandra-driver Installation

$ npm install cassandra-driver

Example

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

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

Couchbase

Module: couchnode Installation

$ npm install couchbase

Example

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

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

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

CouchDB

Module: nano Installation

$ npm install nano

Example

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

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

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

LevelDB

Module: levelup Installation

$ npm install level levelup leveldown

Example

var levelup = require('levelup')
var db = levelup('./mydb')

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

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

    console.log('name=' + value)
  })
})

MySQL

Module: mysql Installation

$ npm install mysql

Example

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

connection.connect()

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

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

connection.end()

MongoDB

Module: mongodb Installation

$ npm install mongodb

Example

var MongoClient = require('mongodb').MongoClient

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

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

    console.log(result)
  })
})

If you want an object model driver for MongoDB, look at Mongoose.

Neo4j

Module: apoc Installation

$ npm install apoc

Example

var apoc = require('apoc')

apoc.query('match (n) return n').exec().then(
  function (response) {
    console.log(response)
  },
  function (fail) {
    console.log(fail)
  }
)

PostgreSQL

Module: pg-promise Installation

$ npm install pg-promise

Example

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

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

Redis

Module: redis Installation

$ npm install redis

Example

var client = require('redis').createClient()

client.on('error', function (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', function (err, replies) {
  console.log(replies.length + ' replies:')

  replies.forEach(function (reply, i) {
    console.log('    ' + i + ': ' + reply)
  })

  client.quit()
})

SQL Server

Module: tedious Installation

$ npm install tedious

Example

var Connection = require('tedious').Connection;
var Request = require('tedious').Request;

var config = {
  userName: 'your_username', // update me
  password: 'your_password', // update me
  server: 'localhost'
}

var connection = new Connection(config);

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

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

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

  connection.execSql(request);
}

SQLite

Module: sqlite3 Installation

$ npm install sqlite3

Example

var sqlite3 = require('sqlite3').verbose()
var db = new sqlite3.Database(':memory:')

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

  for (var i = 0; i < 10; i++) {
    stmt.run('Ipsum ' + i)
  }

  stmt.finalize()

  db.each('SELECT rowid AS id, info FROM lorem', function (err, row) {
    console.log(row.id + ': ' + row.info)
  })
})

db.close()

ElasticSearch

Module: elasticsearch Installation

$ npm install elasticsearch

Example

var elasticsearch = require('elasticsearch')
var client = elasticsearch.Client({
  host: 'localhost:9200'
})

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