How to delete multiple rows in php using checkbox? - php

Question

<form action="<?php echo $_SERVER['PHP_SELF'];?>" style="display:inline" method="post">
<input type="submit" name="del" value="Delete">
<br>
<?php
$con=mysql_connect("localhost","root") OR DIE ("cant connect to server".mysql_error());
mysql_select_db("bedanshare") OR DIE ("cannot select db".mysql_error());
$stud=mysql_query("SELECT * FROM studentreg");
$count=mysql_num_rows($stud);
echo "<table border='1'>";
echo "<th><center />#</th>";
echo "<th><center />Student Number</th>";
echo "<th><center />First Name</th>";
echo "<th><center />Last Name</th>";
echo "<th><center />E-mail</th>";
echo "<th><center />Username</th>";
echo "<th><center />Password</th>";
while($row=mysql_fetch_array($stud))
{
echo "<tr>";?>
<td><input name='checkbox[]' type='checkbox' id='checkbox[]' value="<?php echo $row['ID']; ?>">
<?php
echo "<td><center />".$row['ID']."</td>";
echo "<td><center />".$row['Fname']."</td>";
echo "<td><center />".$row['Lname']."</td>";
echo "<td><center />".$row['EmailAddress']."</td>";
echo "<td><center />".$row['Username']."</td>";
echo "<td><center />".$row['Password']."</td>";
echo "</tr>";
}
echo "</table>";
if($del)
{
for($i=0;$i<$count;$i++)
{
$id=$checkbox[$i];
$dels=mysql_query("DELETE FROM studentreg WHERE ID='$id'");
}
}
?>
</form>
how come the code doesnt delete rows? :( help please. no data seem to be affected. ID is my primary key, however when I click delete, nothing happens. i dont think my query is wrong. btw im using checkboxes to delete multiple rows.

Answer 1

There's a condition:
if($del)
Only if it's true it will enter the loop and will start deleting rows.
The problem is that the variable $del is not defined in your code.
Edit:
Change your condition to:
if(array_key_exists('del',$_POST))
and change the next line as well, from:
$id=$checkbox[$i];
to:
$id=$_POST['checkbox'][$i];

Answer 2

In your code there is two bugs.
1. $del is undefined variable.
2. $checkbox[] is undefined variable.
You have to modify above code as shown below:
if(isset($_POST['delete'])) // Not if($del)
$id = $_POST['checkbox'][$i]; // Not $id=$checkbox[$i];