class DBO {

   protected $_host;
   protected $_port;
   protected $_user;
   protected $_pwd;
   protected $_driver;
   protected $_connection;


   protected function getConnection(){
          return $this->_connection;
   }

   function __construct($host,$user,$pwd,$driver,$port =  0 ){
          $this->_host = $host;
          $this->_port = $port;
          $this->_user = $user;
          $this->_pwd = $pwd;
          $this->_driver = $driver;
   }

  function __call($m, $args) {
          if(!function_exists($this->_driver.'_'.$m)) throw new Exception('Функции '.$m.' не существует!');
          return call_user_func_array($this->_driver.'_'.$m,$args);
  }


  function connect($persistent = true){
          if($persistent){
               $pf = 'p';
          }
          $func_name = $this->_driver.'_'.$pf.'connect';
          if(!function_exists($func_name))
               throw new Exception('Функции '.$func_name.' не существует!');
          if($this->_port> 0 )
              $port = ':'.$this->_port;
         $this->_connection = call_user_func($func_name,$this->_host.$port,$this->_user,$this->_pwd);
         if(!$this->_connection)
              throw new Exception($this->errno().": ".$this->error());
         return $this->_connection;
  }

 }

 $dbo_ms = new DBO('server1','sa','blabla','mssql');
 $dbo_ms->connect();
 $dbo_ms->select_db('Northwind') or die ( $dbo_ms->error());
 $r_ms = $dbo_ms->query('select * from Orders');

 $dbo_my = new DBO('server2','root','blabla','mysql');
 $dbo_my->connect();
 $dbo_my->select_db('dbname') or die ( $dbo_my->error());
 $r_my = $dbo_my->query('select * from `tablename`');

$rs = new DataSet('trade');
$rs->params['id']  = $same_id;
$rs->Open('vendor');
$row = $rs->Fetch();