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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 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
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 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
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’).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)
})
})
示例（v3.*）
var MongoClient = require(‘mongodb’).MongoClient
MongoClient.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)
})
