集成数据库

集成数据库
为 Express 应用添加连接数据库的能力，只需要加载相应数据库的 Node.js 驱动即可。这里将会简要介绍如何为 Express 应用添加和使用一些常用的数据库 Node 模块。

Cassandra
CouchDB
LevelDB
MySQL
MongoDB
Neo4j
PostgreSQL
Redis
SQLite
ElasticSearch
这些数据库驱动只是其中一部分，可在 npm 官网 查找更多驱动。

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]);
});

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(body);
}
});

//Get a list of all books
books.list(function(err, body){
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‘
});

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: mongoskin
安装

$ npm install mongoskin
示例

var db = require(‘mongoskin‘).db(‘localhost:27017/animals‘);

db.collection(‘mamals‘).find().toArray(function(err, result) {
if (err) throw err;
console.log(result);
});
If you want a object model driver for MongoDB, checkout 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);
}
);

PostgreSQL
模块: pg
安装

$ npm install pg
示例

var pg = require(‘pg‘);
var conString = "postgres://username:password@localhost/database";

pg.connect(conString, function(err, client, done) {

if (err) {
return console.error(‘error fetching client from pool‘, err);
}
client.query(‘SELECT $1::int AS number‘, [‘1‘], function(err, result) {
done();
if (err) {
return console.error(‘error running query‘, err);
}
console.log(result.rows[0].number);
});

});

Redis
模块: redis
安装

$ npm install redis
示例

var client = require(‘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();

});

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);
});