Wordpress custom table update not working - php

Question

I'm trying to update wp_table (custom table) via frontend.
i want update records in self submitted page $_SERVER['PHP_SELF']
after update sucesfully i want redirect user to home page. but not working
$domain = $_POST['domain'];
$appointment = $_POST['appointment'];
$rid = $_POST['rid'];
global $wpdb;
if (!isset($_POST['save'])) {
if (mysql_query("UPDATE wp_domain SET domain='$domain', appointmenttime_setting='$appointment' WHERE re_id=$rid"))
{
//echo "UPDATE wp_domain SET domain='$domain', cron_setting='$twitime' WHERE re_id=$rid";
header( 'Location:http://localhost/thepost/?page_id=17' ) ;
}
}
My html code is here
<form method="post" action="<?php $_SERVER['PHP_SELF'] ?>">
<table width="300" border="1">
<tr style="width:450px;">
<td>Domain</td>
<td>
<?php
$act = $Rrow->active_not;
if($act=="NO")
{ ?>
<input name="domain" value="<?php echo $Rrow->domain; ?>" type="text">
<?php
}
else
{
echo $Rrow->domain;
}
?>
</td>
</tr>
<tr>
<td>Appointment Time</td>
<td><select name="appointment">
<option value="5 Minute">5 Minute</option>
<option value="10 Minute">10 Minute</option>
<option value="15 Minute">15 Minute</option>
<option value="30 Minute">30 Minute</option>
<option value="45 Minute">45 Minute</option>
<option value="1 Hour">1 Hour</option>
</select>
<input type="hidden" name="rid" value="<?php echo $Rrow->re_id; ?>" />
</td>
</tr>
<tr>
<td><a class="btn">SAVE</a></td>
<td><input name="save" id="save" type="submit" /></td>
</tr>
</table>
</form>

Answer 1

I feel your issue is with if (!isset($_POST['save'])) and mysql_query instead of wp_query, try like this
if (isset($_POST['save'])) {
if (wp_query("UPDATE wp_domain SET domain='$domain', appointmenttime_setting='$appointment' WHERE re_id=$rid")){
header( 'Location:http://localhost/thepost/?page_id=17' ) ;
exit;
}
}