How to work with checkboxes in relation to database? - php

Question

Hi I am trying to build a form with checkboxes and upon submitting the form, I want to see which checkboxes were checked and update the database accordingly. How is this done? I've tried so many different code and none of them worked. The closest I've gotten was to update only the checked ones. I also need to update the database if they are unchecked as well like a toggle.
So far my code is like this for the form
<form action="" method="post">
<input type=checkbox" value="<?php echo member['id']; ?>" name="member[]" />
<input type="submit" name="update" value="Update" />
</form>
And for the PHP loop I have (excerpt)
foreach ((array)$_POST['test'] as $member) :
$sql = "UPDATE `sp_members` SET `allow_test` = '1' WHERE `id` = '$member'";
Since I think the loop only picks up the checkboxes that are checked, it doesn't pick up the ones that were orignally checked and now unchecked...
Any help appreciated!

Answer 1

Simply update everything instead of trying to figure out what changed - if you programmed it yourself, you would have to make your code a lot more complicated, and as the database is already optimized for speed, it's better to just stuff it in the DB and let it handle it.

Answer 2

You could use a ternary operator to set the correct value.
$sql = "UPDATE `sp_members` SET `allow_test` = '"
. ( $_REQUEST['checkbox'] ? 1 : 0 )
. "' WHERE `id` = '" . mysql_real_escape_string( $member ) . "'";
It checks $_REQUEST['checkbox'] for a non-null, non-zero string and if true, returns 1, if false, returns 0.

Answer 3

(($_post['member']) ?$allow_test = 1 : $allow_test = 0;
$sql = "UPDATE `sp_members` SET `allow_test` = $allow_test WHERE `id` = '$member'";

Answer 4

The reason why this hasn't been working (and won't in the already provided answers) is because checkboxes that are not checked won't exist in the $_POST/$_REQUEST arrays. The other side of that is if they do exist, they must be true.
When you're doing the check to see what the value is, you are causing an error because the key to the array doesn't exist.
Instead, you need to know the available checkboxes and then check if each isset() in the array.
Webform:
<form action="foo.php" method="post">
<input type="checkbox" value="<?php echo $value1; ?>" name="checkbox1" />
<input type="checkbox" value="<?php echo $value2; ?>" name="checkbox2" />
<input type="submit" name="update" value="Update" />
</form>
PHP:
$checkboxes = array(
'column1' => 'checkbox1',
'column2' => 'checkbox2',
);
foreach ($checkboxes as $column => $checkbox)
{
$value = (isset($_POST[$checkbox]) ? 1 : 0);
$sql = "UPDATE `table` SET `$column` = '$value' WHERE `id` = '$member'";
}

Answer 5

When confronted with this, I usually punt and rely on a transaction to update this stuff for me. As you've discovered, unchecked checkboxes won't get submitted with the form, so you'd have to do tedious comparisons to figure out what's changed each time and build up an appropriate update and/or delete query sequence.
Instead, I fire up a transaction, delete all the old checkbox values stored in the DB, and then insert the new ones submitted with this request. Unless you've got the checkboxes acting as foreign keys and/or triggers set on them at the DB level, this is a relatively lightweight option and saves you the trouble of having to compare the old and new lists for changes.