public function deleteAll($fields, $type = null)
 {
     if (!is_array($fields)) {
         $fields = array($fields);
     }
     if (!$fields) {
         return;
     }
     switch ($type) {
         case 'person':
             $cwhere = " WHERE c.is_company=0 ";
             break;
         case 'company':
             $cwhere = " WHERE c.is_company>0 ";
             break;
         default:
             $cwhere = '';
     }
     $set = array();
     foreach ($fields as $id) {
         switch ($id) {
             case 'birthday':
                 $value = "'0000-00-00'";
                 break;
             case 'photo':
                 $value = 0;
                 break;
             default:
                 $value = "''";
                 break;
         }
         $set[] = "`{$id}`={$value}";
     }
     $set = implode(',', $set);
     if (!$this->model) {
         $this->model = new waContactModel();
     }
     $this->model->exec("UPDATE wa_contact AS c SET " . $set . $cwhere);
 }