Decrementing not working?

[downah]

Hi guys, I have written this code, it might look messy but I am learning so I don't really mind that but my main concern is that it is not working, could anyone help me out?

 

I am using an array to "unsubscribe" from multiple events at once, now I also need to decrement the amount of participants in that event, the code is working I am able to unsubscribe from events but the currentparticipants field is not updating.. any idea why?

 

This is the code that runs when you click unsubscribe :

 

if(isset($_POST['eventsID']) && count($_POST['eventsID']))
{
$eventsID = $_POST['eventsID'];

    //Ensure values are ints
    $deleteIDs = implode(', ', array_map('intval', $_POST['eventsID']));
    $query = "DELETE FROM Eventparticipants WHERE eventsID IN ({$deleteIDs})";
    //Debug line
echo '';
    mysql_query($query) or die(mysql_error());
    $result5=mysql_query("SELECT maxparticipants, currentparticipants FROM Events WHERE eventsID='$eventsID'");
$row5=mysql_fetch_assoc($result5);

$currentparticipants = $row5['currentparticipants'];
$maxparticipants = $row5['maxparticipants'];

$newcurrentparticipants = $currentparticipants--;



$sql="UPDATE Events SET currentparticipants='$newcurrentparticipants'
WHERE eventsID='$eventsID'";

if (!mysql_query($sql))
  {
  die('Error: ' . mysql_error());
  }

}

 

And here is the code where you actually click unsubscribe

 

     $result2 = mysql_query("SELECT * FROM Eventparticipants WHERE participant = '$username'")
or die(mysql_error());

echo '</br><b>You are currently taking place in these events: </b></br>';
echo "<form action='' method='POST' onsubmit='return executeOnSubmit();'>";
echo '<table border="0">';
while($row2 = mysql_fetch_array($result2))
{


echo '<tr>';
echo '<td><a href="showevent.php?eventsID=';
echo $row2['eventsID'];
echo '">';
echo $row2['eventdescriptionheader'];
echo '</a></td>';


echo "<td><input type='checkbox' name='eventsID[]' value='{$row2['eventsID']}' /></td>";
echo '</tr>';


}
echo '</table>';
      echo "</br><input type='submit' value='Unsubscribe to event(s)' name='delete' />";
        echo '</form>';

 

 

And here is the full script in one

<?php
include 'connect.php';
include_once "markdown.php";
session_start();

if(!isset($_SESSION['username']))
{
     	echo 'You have to be a registered member to be able to view your space.<br><br> <a href="register.html">Click here to register</a>';
     	       	echo '<br><br><br><br>Or if you are already a member, please login to use this area.<br>';
       	echo '
       	<form method="POST" action="loginverification.php">
       	<table border="0">
       	<tr><td>
  Username: </td><td><input type="text" name="username" size="15" /></td></tr>
  <tr><td>Password:</td><td> <input type="password" name="password" size="15" /></td></tr>
  </table>
  <div align="center">
    <p><input type="submit" value="Login" /></p>
  </div>
</form>';
}
else{

if(isset($_POST['eventsID']) && count($_POST['eventsID']))
{
$eventsID = $_POST['eventsID'];

    //Ensure values are ints
    $deleteIDs = implode(', ', array_map('intval', $_POST['eventsID']));
    $query = "DELETE FROM Eventparticipants WHERE eventsID IN ({$deleteIDs})";
    //Debug line
echo '';
    mysql_query($query) or die(mysql_error());
    $result5=mysql_query("SELECT maxparticipants, currentparticipants FROM Events WHERE eventsID='$eventsID'");
$row5=mysql_fetch_assoc($result5);

$currentparticipants = $row5['currentparticipants'];
$maxparticipants = $row5['maxparticipants'];

$newcurrentparticipants = $currentparticipants--;



$sql="UPDATE Events SET currentparticipants='$newcurrentparticipants'
WHERE eventsID='$eventsID'";

if (!mysql_query($sql))
  {
  die('Error: ' . mysql_error());
  }

}



       $username = $_SESSION['username'];


       $result = mysql_query("SELECT * FROM Members WHERE username = '$username'")
               or die(mysql_error());
               while($row = mysql_fetch_array($result))
               {
                       echo '<b>' . $username . '</b></br></br>';


     echo '<img src="data:image/jpg/png/jpeg;base64,' . base64_encode( $row['image'] ) . '" height="150" />';
     echo '</br>';


$selfdescription = Markdown($row['selfdescription']);
                       echo $selfdescription;
                       echo '</br></br>';
echo '<table border="0">';

echo '<tr>';
echo '<td>';
echo 'Email: ';
echo '</td>';
echo '<td><b>';
echo $row['email'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Date joined: ';
echo '</td>';
echo '<td><b>';
print date('d M Y', strtotime($row['datejoined']));
echo "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Last visit: ';
echo '</td>';
echo '<td><b>';
print date('d M Y', strtotime($row['lastvisit']));
echo "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'First name: ';
echo '</td>';
echo '<td><b>';
echo $row['firstname'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Family name: ';
echo '</td>';
echo '<td><b>';
echo $row['familyname'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Date of birth: ';
echo '</td>';
echo '<td><b>';
print date('d M Y', strtotime($row['dob']));
echo "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Gender: ';
echo '</td>';
echo '<td><b>';
echo $row['gender'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'County: ';
echo '</td>';
echo '<td><b>';
echo $row['county'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo 'Postcode: ';
echo '</td>';
echo '<td><b>';
echo $row['postcode'] . "</b>";
echo '</td>';
echo '</tr>';

echo '<tr>';
echo '<td>';
echo '</br>';
echo '<form action="editprofile.php">';
echo '<input type="submit" name="" value="Edit Profile">';
echo '</form>';
echo '</td>';
echo '</tr>';

echo '</table>';

               }

            $result2 = mysql_query("SELECT * FROM Eventparticipants WHERE participant = '$username'")
or die(mysql_error());

echo '</br><b>You are currently taking place in these events: </b></br>';
echo "<form action='' method='POST' onsubmit='return executeOnSubmit();'>";
echo '<table border="0">';
while($row2 = mysql_fetch_array($result2))
{


echo '<tr>';
echo '<td><a href="showevent.php?eventsID=';
echo $row2['eventsID'];
echo '">';
echo $row2['eventdescriptionheader'];
echo '</a></td>';


echo "<td><input type='checkbox' name='eventsID[]' value='{$row2['eventsID']}' /></td>";
echo '</tr>';


}
echo '</table>';
      echo "</br><input type='submit' value='Unsubscribe to event(s)' name='delete' />";
        echo '</form>';

                            $result4 = mysql_query("SELECT * FROM Events WHERE hoster = '$username'")
or die(mysql_error());

echo '</br><b>You are currently hosting these events: </b></br>';
echo "<form action='' method='POST'>";
echo '<table border="0">';
while($row4 = mysql_fetch_array($result4))
{


echo '<tr>';
echo '<td><a href="showevent.php?eventsID=';
echo $row4['eventsID'];
echo '">';
echo $row4['eventdescriptionheader'];
echo '</a></td>';



echo '</tr>';


}
echo '</table>';

        echo '</form>';

}


?>

 

Much appreciated!

[PFMaBiSmAd]

A simple way of fixing this (and reducing the amount of code and data you have) is to simply COUNT() (inside a query statement) the number of participants for any event. By storing a separate number, you are creating redundant data that now must be maintained.

[downah]

Thanks for the suggestion, I am have not used the count function before, but I need this field and there must be something small wrong with why its not updating? Anyone else have any ideas why it is not decreasing the current participants by one?

[downah]

Now using this but still the same problem, the currentparticipants is not decreasing by one, any ideas?

 

	if(isset($_POST['eventsID']) && count($_POST['eventsID']))
{
$eventsID = $_POST['eventsID'];

    //Ensure values are ints
    $deleteIDs = implode(', ', array_map('intval', $_POST['eventsID']));
    $query = "DELETE FROM Eventparticipants WHERE eventsID IN ({$deleteIDs})";
    //Debug line
echo '';
    mysql_query($query) or die(mysql_error());
    $result5=mysql_query("SELECT maxparticipants, currentparticipants FROM Events WHERE eventsID='$eventsID'");
$row5=mysql_fetch_assoc($result5);

$currentparticipants = $row5['currentparticipants'];




$b[] = $eventsID;

mysql_query("UPDATE Events SET `eventsID` = (`currentparticipants` - 1) WHERE `eventsID` IN(" . implode(',', $b) . ")") or trigger_error('MySQL Update Failed: ' . mysql_error());
}

[downah]

FIXED! I am getting a hang of this slowly but surely.

 

here is the working script  if it is any help for anyone else

 

if(isset($_POST['eventsID']) && count($_POST['eventsID']))
{
$eventsID = $_POST['eventsID'];

    //Ensure values are ints
    $deleteIDs = implode(', ', array_map('intval', $_POST['eventsID']));
    $query = "DELETE FROM Eventparticipants WHERE eventsID IN ({$deleteIDs})";
    //Debug line
echo '';
    mysql_query($query) or die(mysql_error());
    $result5=mysql_query("SELECT maxparticipants, currentparticipants FROM Events WHERE eventsID='$eventsID'");
$row5=mysql_fetch_assoc($result5);

$currentparticipants = $row5['currentparticipants'];


mysql_query("UPDATE Events SET `currentparticipants` = (`currentparticipants` - 1) WHERE `eventsID` IN ({$deleteIDs})") or trigger_error('MySQL Update Failed: ' . mysql_error());
}