controllo username vietati

[rocco.mod]

io uso un discorso tipo cosi

if(!isset($user_allowed)OR $user_allowed  ==''){
echo"Il campo titolo e obbligatorio";
echo"<script type=\"text/javascript\">";
echo"setTimeout(\"location.href='setting.php?setting=security_setting'\",3000)";
echo"</script>";
return;
}else{
$controllo_user_name_allowed = mysql_query("SELECT * FROM username_vietati WHERE user_nomi_vietati ='$user_allowed'");
if(@mysql_num_rows($controllo_user_name_allowed)!=0){
echo"L user e gia presente nel database";
echo"<script type=\"text/javascript\">";
echo"setTimeout(\"location.href='setting.php?setting=security_setting'\",3000)";
echo"</script>";
}else{


$modifico_username_vietati = mysql_query("UPDATE username_vietati SET user_nomi_vietati='$user_allowed' WHERE id='1'");
if($modifico_username_vietati){
echo"Modifica effettuata";
echo"L user e gia presente nel database";
echo"<script type=\"text/javascript\">";
echo"setTimeout(\"location.href='setting.php?setting=security_setting'\",3000)";
echo"</script>";

}else{
echo "errore".mysql_error();
}
}
}