¥Database integration
添加将数据库连接到 Express 应用的功能只需为应用中的数据库加载适当的 Node.js 驱动程序即可。本文档简要说明了如何在 Express 应用中为数据库系统添加和使用一些最流行的 Node.js 模块：
¥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:
这些数据库驱动程序是许多可用的数据库驱动程序之一。对于其他选项，请在 npm 网站上搜索。
¥These database drivers are among many that are available. For other options, search on the npm site.
¥Module: cassandra-driver
¥Installation
$ npm install cassandra-driver
¥Example
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])
})
模块：couchnode
¥Module: couchnode
¥Installation
$ npm install couchbase
¥Example
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)
}
})
模块：nano
¥Module: nano
¥Installation
$ npm install nano
¥Example
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)
}
})
模块：levelup
¥Module: levelup
¥Installation
$ npm install level levelup leveldown
¥Example
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}`)
})
})
模块：mysql
¥Module: mysql
¥Installation
$ npm install mysql
¥Example
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()
模块：mongodb
¥Module: mongodb
¥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)
})
})
如果你想要 MongoDB 的对象模型驱动程序，请查看 Mongoose。
¥If you want an object model driver for MongoDB, look at Mongoose.
模块：neo4j-driver
¥Module: neo4j-driver
¥Installation
$ npm install neo4j-driver
¥Example
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)
})
})
模块：oracledb
¥Module: oracledb
¥Installation
注意：查看安装先决条件。
¥NOTE: See installation prerequisites.
$ npm install oracledb
¥Example
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)
模块：pg-promise
¥Module: pg-promise
¥Installation
$ npm install pg-promise
¥Example
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)
})
模块：redis
¥Module: redis
¥Installation
$ npm install redis
¥Example
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()
})
模块：tedious
¥Module: tedious
¥Installation
$ npm install tedious
¥Example
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)
}
模块：sqlite3
¥Module: sqlite3
¥Installation
$ npm install sqlite3
¥Example
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
¥Installation
$ npm install elasticsearch
¥Example
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)
})