en/guide/database-integration.md
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:
Module: cassandra-driver
$ npm install cassandra-driver
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])
})
Module: couchnode
$ npm install couchbase
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)
}
})
Module: nano
$ npm install nano
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)
}
})
Module: levelup
$ npm install level levelup leveldown
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}`)
})
})
Module: mysql
$ npm install mysql
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()
Module: mongodb
$ npm install mongodb
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)
})
})
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.
Module: neo4j-driver
$ npm install neo4j-driver
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)
})
})
Module: oracledb
NOTE: See installation prerequisites.
$ npm install oracledb
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)
Module: pg-promise
$ npm install pg-promise
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)
})
Module: redis
$ npm install redis
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()
})
Module: tedious
$ npm install tedious
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)
}
Module: sqlite3
$ npm install sqlite3
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()
Module: elasticsearch
$ npm install elasticsearch
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)
})