$query = $db->query("SELECT * FROM uyeler", PDO::FETCH_ASSOC);
if ( $query->rowCount() ){
     foreach( $query as $row ){
          $query = $db->prepare("UPDATE uyeler SET   token= :token WHERE id = :id");
            $update = $query->execute(array(
                 "token" => idS(),
                 "id" => $row['id']
            ));
            if ( $update ){
                 echo "güncellendi";
            }else{
                echo "bir sorun var";
            }
     }
}