Deleting database values Using PHP, not working

Question

I am trying to delete multiple values from my form (its a car rental system, where I want to give the staff the ability to delete a car from the record). I am new to PHP but this is what I have right now.

<?php
$link = mysql_connect ("xxxx", "xxxx", "xxxx");
mysql_select_db ("xxxx");

    $query = "SELECT * from car";
    $result = mysql_query ($query);
    echo ("<form action=\"deleting2.php\" method=\"GET\">");
    echo "<table id = 'table-3'>";
    echo "<thead>";
    echo "<th>Car ID</th>
    <th>Car Name</th>
    <th>Fuel Type</th>
    <th>Transmission</th>
    <th>Engine Size</th>
    <th>Doors</th>
    <th>Total</th>
    <th>Available</th>
    <th>Date Added</th>
    <th>Delete</th> ";
    echo "</thead>";
    for ($i = 0; $i < mysql_num_rows ($result); $i ++)
      {        
       $row = mysql_fetch_object ($result);
       echo "<tbody>";
       echo "<tr>";
       echo "<td>$row->ID</td>";
       echo "<td>$row->CARNAME</td>";
       echo "<td>$row->FUELTYPE</td>";
       echo "<td>$row->TRANSMISSION</td>";
       echo "<td>$row->ENGINE_SIZE</td>";
       echo "<td>$row->DOORS</td>";
       echo "<td>$row->TOTAL</td>";
       echo "<td>$row->AVAILABLE</td>";
       echo "<td>$row->DATEADDED</td>";
       echo "<td><input type='checkbox' name='delete[]' value='$row->ID' /></td>";
       echo "</tr>";
       echo "</tbody>";
      }
      echo ("<tr><td colspan='6' align='center'><input type=\"submit\" value=\"Delete  \"></td> </tr></table></form>");
      echo  "</table>";
      mysql_close ($link);
      ?>

Now,when I do press the delete button, it goes to my php page called 'deleting2.php' as mentioned in the form action, which has the following code:

<?php
$link = mysql_connect ("xxxx", "xxxx", "xxxx");
mysql_select_db ("xxxx");

$ID='$_GET[ID]';

// DELETE ANY RECORDS IN DATABASE
for ($i = 0; $i < @mysql_num_rows ($result); $i ++)
{
if(isset($_GET['delete[]']) && $_GET['delete[]']=='$row->ID');
{
   $query=("DELETE FROM car WHERE ID='$_POST[ID]'");
    $result1 = mysql_query($query);
}
}
mysql_close ($link);

?>

The problem is, it is NOT deleting anything from the my database. The URL in the address bar when the deleting2.php is being processed, is:

http://www.computing.northampton.ac.uk/~11430900/a1/webpages/deleting2.php?delete[]=6

Which according to my knowledge, selects the values that were ticket. Here, I had checked the box, which had a corresponding ID value of 6. So, check-box DOES work, it just does not do anything to the database, does not delete the value. I have tried many tutorials but I can't delete it using check-boxes. Any help would be much appreciated.

$ID='$_GET[ID]'; and DELETE FROM car WHERE ID='$_POST[ID]'; use GET or POST not both — Nirav Ranpara
– Nirav Ranpara, Commented Dec 10, 2012 at 13:36
Please have a look at some articles about mysql injection en.wikipedia.org/wiki/SQL_injection — Jelmer
– Jelmer, Commented Dec 10, 2012 at 13:38

dkkumargoyal · Accepted Answer · 2012-12-10 13:55:00Z

1

You don't need to itrate through following loop as mentioned in your question

for ($i = 0; $i < @mysql_num_rows ($result); $i ++)
{
if(isset($_GET['delete[]']) && $_GET['delete[]']=='$row->ID');
{
   $query=("DELETE FROM car WHERE ID='$_POST[ID]'");
    $result1 = mysql_query($query);
}
}
mysql_close ($link);

just to the following.

change your form method to POST.

use the following code. implode is necessary as $_POST['delete'] will be an array

if(isset($_POST['delete']) && count($_POST['delete']) > 0) {
    $query=("DELETE FROM car WHERE ID in ('".implode(',',$_POST['delete'])."')");
    $result1 = mysql_query($query);
}

answered Dec 10, 2012 at 13:55

dkkumargoyal

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Comments

webnoob · Accepted Answer · 2012-12-10 13:41:05Z

0

Your data needs sanitizing but this should be Ok if you expect the ID to be a number:

$id = (int)$_GET['ID'];    
$query=("DELETE FROM car WHERE ID=$id");

You really need to look at the rest of your code for SQL injection attacks.

answered Dec 10, 2012 at 13:41

webnoob

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1 Comment

G_R Over a year ago

will look into sql injection. As I said I am new to this, gonna try it out. Thank you :)

shadyyx · Accepted Answer · 2012-12-10 13:47:47Z

0

First of all, be very carefull when implementing a database entries deletion as You could end up with empty database.

Secondly, always sanitize Your input to prevent SQL Injection.

Thirdly, learn PDO or at least mysqli_* functions instead of mysql_ as they are deprecated now and could be removed with any next PHP release.

Now, to Your problem, You are setting the ID values into a delete[] array value, that means You should do this:

// DELETE THE DESIRED RECORDS IN DATABASE
foreach($_GET['delete'] as $id) {
    $result = mysql_query("DELETE FROM car WHERE ID = '" . mysql_real_escape_string($id) . "'");
    // do something with the $result here ...
}

Other option could be to expect only integers:

// DELETE THE DESIRED RECORDS IN DATABASE
foreach($_GET['delete'] as $id) {
    $result = mysql_query("DELETE FROM car WHERE ID = '" . (int)$id . "'");
    // do something with the $result here ...
}

answered Dec 10, 2012 at 13:47

shadyyx

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3 Comments

G_R Over a year ago

i AM trying all suggestion, but its still not deleting.

G_R Over a year ago

ok it WORKED! the working script is this: <?php $link = mysql_connect ("xxxx", "xxxx", "xxxx"); mysql_select_db ("xxxx"); $ID='$_GET[ID]'; // DELETE ANY RECORDS IN DATABASE foreach($_GET['delete'] as $id) { $result = mysql_query("DELETE FROM car WHERE ID = '" . mysql_real_escape_string($id) . "'"); } mysql_close ($link); header("location: list_logged.php"); ?>

shadyyx Over a year ago

@GauravRavindra Glad I could help. Now accept the answer if Your problem is solved, please.

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