function getLicenseCategories($id=""){
        $where = "";
         if($id)
           $where=" WHERE id in (".$id.");";

           $query = "SELECT * FROM ".$this->getPrefix()."license_categories".$where;
         $result = $this->Execute($query);

         if (!$result||$result->RecordCount()<1)
            return false;
        if($id!=""){
              $row = $result->FetchRow();
             return $this->_fetchLicenseInfomation($row);
             }       
        else{
             $licenseCategories = Array ();
             while ($row = $result->FetchRow()) {
                 array_push($licenseCategories, $this->_fetchLicenseInfomation($row));
              }
             return $licenseCategories;
       }

当有id时候返回$this->_fetchLicenseInfomation($row)为什么比较好。