Intégration de bases de données
L’ajout de la fonctionnalité permettant de connecter des bases de données aux applications Express consiste simplement à charger un pilote Node.js approprié pour les bases de données de votre application. Ce document explique brièvement comment ajouter et utiliser dans votre application Express certains des modules Node.js les plus populaires pour les systèmes de base de données :
- Cassandra
- Couchbase
- CouchDB
- LevelDB
- MySQL
- MongoDB
- Neo4j
- Oracle
- PostgreSQL
- Redis
- SQLite
- ElasticSearch
Ces pilotes de base de données ne sont qu’une partie de ceux disponibles. Pour d’autres options, consultez le site npm.
Cassandra
Module : cassandra-driver Installation
Installation
$ npm install cassandra-driver
Exemple
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
Installation
$ npm install couchbase
Exemple
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 Installation
Installation
$ npm install nano
Exemple
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 Installation
Installation
$ npm install level levelup leveldown
Exemple
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 Installation
Installation
$ npm install mysql
Exemple
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 Installation
Installation
$ npm install mongodb
Example (v2.*)
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.*)
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)
})
})
Si vous voulez un pilote de modèle d’objet pour MongoDB, recherchez Mongoose.
Neo4j
Module : apoc Installation
Installation
$ npm install neo4j-driver
Exemple
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
Installation
Remarque: Voir les conditions préalables à l’installation.
$ npm install oracledb
Exemple
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 Installation
Installation
$ npm install pg-promise
Exemple
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 Installation
Installation
$ npm install redis
Exemple
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
Installation
$ npm install tedious
Exemple
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 Installation
Installation
$ npm install sqlite3
Exemple
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 Installation
Installation
$ npm install elasticsearch
Exemple
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)
})