/**
 +----------------------------------------------------------
 * 对保存到数据库的数据进行处理
 +----------------------------------------------------------
 * @access protected
 +----------------------------------------------------------
 * @param mixed $data 要操作的数据
 +----------------------------------------------------------
 * @return boolean
 +----------------------------------------------------------
 */
 protected function _facade($data)
 {
     // 检查序列化字段
     $data = $this->serializeField($data);
     return parent::_facade($data);
 }