protected function _prepareStatement()
 {
     parent::_prepareStatement();
     foreach (array_keys($this->lobDescriptors) as $name) {
         if (!oci_bind_by_name($this->statement, ':p_' . $name, $this->lobDescriptors[$name], -1, $this->lobs[$name]->getNativeType())) {
             $this->connection->_raiseError($this->statement);
         }
     }
 }