Remove items in database based on status of checkbox

Question

I am trying to take input from an HTML form where there are checkboxes. The checkboxes are created with the student_ids from the database. Like so:

 <td><input type="checkbox" name="{$row['STUDENT_ID']}" />

What I want to do is step through the Students table and check all of the entries against which of the checkboxes are checked. I want to then delete the entries from the database that have been checked with the checkboxes.

  8    $query = "SELECT STUDENT_ID From Students";
  9 $result = mysql_query($query) or die(mysql_error());
 10 while($row=mysql_fetch_array($result)){
 11   $checkname=$row['STUDENT_ID'];
 12   foreach($_POST[$checkname] as $student_id =>val)
 13   {
 14   if($val == 'YES'
 15     {
 16       echo $_POST['STUDENT_ID'];
 17       $query = "DELETE FROM Students WHERE STUDENT_ID" . mysql_real_escape_string($STUDENT_ID);
 18     }
 19   echo $query;
 20   $result = mysql_query($query) or die(mysql_error());
 21   //echo $POST['STUDENT_ID'];
 22 }
 23 }

David Bélanger · Accepted Answer · 2011-10-24 19:02:04Z

1

Create an array of checkbox :

    <input type="checkbox" name="studentID[]" value="{$row['STUDENT_ID']}" />

From PHP :

    $studentID = $_POST['studentID'];

    foreach($studentID as $ID){
        echo $ID.'<br />'."\n";
    }

EDIT : Not sure but I think this is the right way :

    $studentID = $_POST['studentID'];

    $i=0;
    foreach($studentID as $ID){
        $i++;
        echo $_POST['studentID'][$i].'<br />'."\n";
    }

answered Oct 24, 2011 at 19:02

David Bélanger

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Comments

phpSteve · Accepted Answer · 2011-10-24 19:01:26Z

0

Try this for your form:

<input type="checkbox" name="STUDENT_ID[<?php echo $row['STUDENT_ID'] ?>]" value="YES" />

and this for your PHP loop:

foreach ($_POST['STUDENT_ID'] as $student_id => $val) {
    if ($val == 'YES') {
        $query = "DELETE FROM Students WHERE STUDENT_ID=" . mysql_real_escape_string($student_id);
        $result = mysql_query($query) or die(mysql_error());
    }
}

answered Oct 24, 2011 at 19:01

phpSteve

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Aaron W. · Accepted Answer · 2011-10-24 19:04:22Z

0

A better way of doing this is to take the Student IDs from your checkboxes that were submitted and then run deletes on those.

HTML

<input type="checkbox" name="students_to_delete[]" value="{$row['STUDENT_ID']}" />

PHP

$students_to_delete = $_POST['students_to_delete'];
if(is_array($students_to_delete) && count($students_to_delete) > 0) {
    $query = "DELETE FROM Students WHERE STUDENT_ID IN (" . implode(",", $students_to_delete) . ")";
    $result = mysql_query($query) or die(mysql_error());
}

answered Oct 24, 2011 at 19:04

Aaron W.

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Comments

Alan Savage · Accepted Answer · 2011-10-24 19:04:37Z

0

The above code is vulnerable to SQL injection. If someone posts back to the server a value of 0 OR STUDENT_ID!=0 then all rows in the Students table will be deleted.

Your code is also inefficient - you are returning all the students and then iterating over each student to see if this requires deleting.

You would be better using in your markup:

<input type="checkbox" name="STUDENT_TO_DELETE" value="$row['STUDENT_ID']" />

and then in the php:

foreach ($_POST['STUDENT_TO_DELETE'] as $student_id => $val) { $sql = "DELETE FROM Students WHERE STUDENT_ID=" . mysql_real_escape_string($student_id); mysql_query($sql); } }

answered Oct 24, 2011 at 19:04

Alan Savage

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