working with foreach in mysql and php.

working with foreach in mysql and php.

I have two arrays the selected and questiondesc, I want to update it to
the database but My code doesnt seem to work. Is it possible to do nested
for each?
<?php do { ?><tr><th width="170" scope="col"><input type="checkbox"
name="selected[]" value="<?php echo $row_Recordset1['question_id']; ?>"
/>
Description:</th>
<td colspan="2" scope="col">old:
<?php echo $row_Recordset1['question_description']; ?>
new:<input name="questiondesc[]" type="text" size="50" />/td>
<td width="549" colspan="2" scope="col"><div align="left"></td>
</tr><?php } while ($row_Recordset2 = mysql_fetch_assoc($Recordset2)); ?>
if(isset($_POST['selected'])){
$selected = $_POST['selected'];
$question = $_POST['questiondesc'];
foreach($selected as $enable) {
mysql_query("UPDATE exam_questions SET question_description = '$question'
WHERE question_id = '$selected' ")or die(mysql_error());
}
}
Thanks :)