$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";
            }
     }
}