Express 文档（数据库集成）

数据库集成添加将数据库连接到Express应用程序的功能只需在应用程序中为数据库加载适当的Node.js驱动程序，本文档简要介绍了如何在Express应用程序中为数据库系统添加和使用一些最流行的Node.js模块。这些数据库驱动程序是众多可用的驱动程序，对于其他选项，请在npm网站上搜索。Cassandra模块：cassandra-driver安装$ npm install cassandra-driver示例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模块：couchnode安装$ npm install couchbase示例var couchbase = require(‘couchbase’)var bucket = (new couchbase.Cluster(‘http://localhost:8091’)).openBucket(‘bucketName’)// add a document to a bucketbucket.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 13var n1ql = ‘SELECT d.* FROM bucketName d WHERE shoeSize = $1’var query = N1qlQuery.fromString(n1ql)bucket.query(query, [13], function (err, result) { if (err) { console.log(err) } else { console.log(result) }})CouchDB模块：nano安装$ npm install nano示例var nano = require(’nano’)(‘http://localhost:5984’)nano.db.create(‘books’)var books = nano.db.use(‘books’)// Insert a book document in the books databasebooks.insert({ name: ‘The Art of war’ }, null, function (err, body) { if (err) { console.log(err) } else { console.log(body) }})// Get a list of all booksbooks.list(function (err, body) { if (err) { console.log(err) } else { console.log(body.rows) }})LevelDB模块：levelup安装$ npm install level levelup leveldown示例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模块：mysql安装$ npm install mysql示例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模块：mongodb安装$ npm install mongodb示例（v2.）var MongoClient = require(‘mongodb’).MongoClientMongoClient.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) })})示例（v3.）var MongoClient = require(‘mongodb’).MongoClientMongoClient.connect(‘mongodb://localhost:27017/animals’, function (err, client) { if (err) throw err var db = client.db(‘animals’) db.collection(‘mammals’).find().toArray(function (err, result) { if (err) throw err console.log(result) })})如果你想要MongoDB的对象模型驱动程序，请查看Mongoose。Neo4j模块：apoc安装$ npm install apoc示例var apoc = require(‘apoc’)apoc.query(‘match (n) return n’).exec().then( function (response) { console.log(response) }, function (fail) { console.log(fail) })Oracle模块：oracledb安装注意：请参阅安装前提条件。$ npm install oracledb示例const oracledb = require(‘oracledb’);const config = { user: ‘<your db user>’, // Update me password: ‘<your db password>’, // Update me connectString: ’localhost:1521/orcl’ // Update me};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模块：pg-promise安装$ npm install pg-promise示例var pgp = require(‘pg-promise’)(/options/)var db = pgp(‘postgres://username:password@host:port/database’)db.one(‘SELECT $1 AS value’, 123) .then(function (data) { console.log(‘DATA:’, data.value) }) .catch(function (error) { console.log(‘ERROR:’, error) })Redis模块：redis安装$ npm install redis示例var redis = require(‘redis’)var client = 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模块：tedious安装$ npm install tedious示例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模块：sqlite3安装$ npm install sqlite3示例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模块：elasticsearch安装$ npm install elasticsearch示例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)})