?php
class MongoDB
{
  private $database;
  private $mongo;
  function __construct()
   {
    $this->mongo = new MongoClient("mongodb://user:password@server_address:port/admin");
    $this->database = $this->mongo->selectDB("data");
  }
  {
    return $this->database->selectCollection($collection);
  }
  //获取所有的集合名
  function getCollections() 
  {
    return $this->database->getCollectionNames();
  }
  //选数据库
  function selectDB($db)
  {
    $this->database = $this->mongo->selectDB($db);
  }
}

class DemoController extends CI_Controller
{
  function __construct() {
    parent::__construct();
    //CI中加载类
    $this->load->library('mongo_lib', '', 'mongodb');
  }
  //插入一条数据
  function create()
  {
    $data = array('name'=>'mike','email'=>'abc@163.com);
    //选择库，shell：user demo_db
    $this->mongodb->selectDB('demo_db');
    //选择集合,db.demo_col.insert();
    $rebateCollection = $this->mongodb->getCollection('demo_collection');
    $res = $rebateCollection->insert($data);
  }
}