Intégration de la base de données
Ajouter la possibilité de connecter des bases de données à des applications Express est juste une question de charger un pilote Node.js approprié pour la base de données dans votre application. Ce document explique brièvement comment ajouter et utiliser certains des modules Node.js les plus populaires pour les systèmes de base de données dans votre application Express :
- Cassandra
- Couchbase
- CouchDB
- LevelDB
- MySQL
- MongoDB
- Neo4j
- Oracle
- PostgreSQL
- Redis
- Serveur SQL
- SQLite
- Elasticsearch
Ces pilotes de bases de données sont parmi les nombreux qui sont disponibles. Pour d’autres options, recherchez sur le site npm.
Cassandra
Module : cassandra-driver
Installation
$ npm install cassandra-driverExemple
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 couchbaseExemple
const couchbase = require('couchbase');const bucket = new couchbase.Cluster('http://localhost:8091').openBucket('bucketName');
// add a document to a bucketbucket.insert('document-key', { name: 'Matt', shoeSize: 13 }, (err, result) => { if (err) { console.log(err); } else { console.log(result); }});
// get all documents with shoe size 13const 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
$ npm install nanoExemple
const nano = require('nano')('http://localhost:5984');nano.db.create('books');const books = nano.db.use('books');
// Insert a book document in the books databasebooks.insert({ name: 'The Art of war' }, null, (err, body) => { if (err) { console.log(err); } else { console.log(body); }});
// Get a list of all booksbooks.list((err, body) => { if (err) { console.log(err); } else { console.log(body.rows); }});LevelDB
Module : levelup
Installation
$ npm install level levelup leveldownExemple
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
$ npm install mysqlExemple
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
$ npm install mongodbExemple (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); });});Exemple (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 objet pour MongoDB, regardez Mongoose.
Neo4j
Module : neo4j-driver
Installation
$ npm install neo4j-driverExemple
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] (https://github.com/oracle/node-oracledb#-installation).
$ npm install oracledbExemple
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
$ npm install pg-promiseExemple
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
$ npm install redisExemple
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();});Serveur SQL
Module : tedious
Installation
$ npm install tediousExemple
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
$ npm install sqlite3Exemple
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
$ npm install elasticsearchExemple
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); } );