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)
})