数据库连接问题

文件1

$search_db = new SearchDo();

if ($search_db->connect() === false) { //数据库连接

   exit;

}



if( $area_kubun_id == '') {

        //地域

        $list_area = new AreaList();

        $area_list = $list_area->createList();

        $smarty->assign('area_list', $area_list);

}else {



        $area_list =$search_db->getAreaById($area_kubun_id);

        $smarty->assign('area_list', $area_list);



}

文件2

class AreaList extends SelectList {

    function AreaList(){

        $sql = SQL_AREA_LIST_SELECT;

        $this->sql = $sql;

        $this->SelectList();

    }

}

文件3

class SelectList extends BoatDb {



    function SelectList() {

        $this->BoatDb();

        $this->connect(); // 数据库连接



    }



     function createList() {

        --数据库操作--

        $this->close();// 关闭连接

     }

}