/**
  *
  * @return \ORC\DAO\Dao
  */
 public function getDao()
 {
     if (!isset($this->_dao)) {
         $server_name = $this->_table->getServerName();
         $this->_dao = DaoFactory::get($server_name);
     }
     return $this->_dao;
 }
 /**
  * 
  * @param string/\ORC\DAO\Table $table
  * @param string $op
  * @return \ORC\DBAL\Common\Common
  */
 protected static function create($table, $op = self::SELECT)
 {
     if (is_string($table)) {
         $table = new Table($table);
     }
     if ($table instanceof Table) {
         //first find the engine
         $engine = self::getEngine($table->getServerName());
         $class_name = "\\ORC\\DBAL\\" . $engine . "\\" . $op;
         return new $class_name($table);
     }
 }