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Mỗi một dự án, mỗi một webservice cũng đều kết nối ít nhất một hay nhiều database. Việc lựa chọn database nào cho dự án phù hợp thì tuỳ thuộc vào bạn. Ở bài viết này, chúng tôi sẽ hướng dẫn cách connect database với nodejs với nhiều database như: Cassandra, Couchbase, CouchDB, LevelDB, MySQL, MongoDB...

Connect node js with Oracle

Module: oracledb Installation

$ npm install oracledb 

const oracledb = require('oracledb')
const config = {
  user: '',
  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)

Mongodb nodejs

Module: mongodb Installation

$ npm install mongodb

Example (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)
  })
})

Example (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)
  })
})

Ngoài ra bạn có thể connect với một object model driver for MongoDB đó là Mongoose.

Mysql nodejs

Module: mysql Installation

Đọc thêm: Connect Mysql Nodejs: Convert callback to async/await

$ npm install mysql

Example

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()

Elasticsearch Nodejs

Module: elasticsearch Installation

$ npm install elasticsearch

Example

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)
})

SQLite Nodejs

Module: sqlite3 Installation

$ npm install sqlite3

Example

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()

SQL Server Nodejs

Module: tedious Installation

$ npm install tedious

Example

var Connection = require('tedious').Connection
var Request = require('tedious').Request

var config = {
  server: 'localhost',
  authentication: {
    type: 'default',
    options: {
      userName: 'your_username', // update me
      password: 'your_password' // update me
    }
  }
}

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)
}

Redis Nodejs

Đọc thêm:  Vì sao nói Redis là kẻ huỷ diệt 

Module: redis Installation

$ npm install redis

Example

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()
})

PostgreSQL Nodejs

Module: pg-promise Installation

$ npm install pg-promise

Example

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)
  })

Neo4j Nodejs

Module: apoc Installation

$ npm install apoc

Example

var apoc = require('apoc')

apoc.query('match (n) return n').exec().then(
  function (response) {
    console.log(response)
  },
  function (fail) {
    console.log(fail)
  }
)

LevelDB Nodejs

Module: levelup Installation

$ npm install level levelup leveldown

Example

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)
  })
})

CouchDB

Module: nano Installation

$ npm install nano

Example

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)
  }
})

Couchbase

Module: couchnode Installation

$ npm install couchbase

Example

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)
  }
})

Cassandra

Module: cassandra-driver Installation

$ npm install cassandra-driver

Example

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])
})

Source:  expressjs.com