PHP Delete record from database MySql

Question

I need to delete a record, in this case a categories from my forum, from the database based on its id.

<?php
    if(isset($_SESSION['signed_in']) && $_SESSION['user_level'] == 1)
    {
?>
    <td>
        <form method="post">
            <input type="hidden" value="<?= ['cat_id']; ?>">
            <input type="submit" name="submit" value="Remover" />
        </form>
    <?php
        if(isset($_POST['submit']))
        {
            mysql_query("DELETE FROM categories where cat_id = 'cat_id'");
        }
    ?>
    </td>
<?php
}
?>

i cant get a "good" way to do it... :(

EDIT: This is for a programming lesson not a real forum!!

whats the value in input type hidden, m sure its not a variable. — sunny
– sunny, Commented Mar 20, 2014 at 12:18
you might want to describe your problem in more detail. i.e. "It does not delete" or "an error message is shown" and so on ... — Andresch Serj
– Andresch Serj, Commented Mar 20, 2014 at 12:18

Community · Accepted Answer · 2023-11-17 19:30:35Z

1

Your HTML Input Field needs a name so it can be identified by your PHP. Then, in your Code Block where you attempt to delete the category, you need to acces the category id using the $_POST array.

Another thig you want to do is read up onj the dangers of SQL injections. If you're just playing around with PHP and MySQL at the moment: Go Ahead. But if you actually want to develop, maybe you should read up on a few other things as well, even if it seems like overkill at first: PHP The Right Way.

Nontheless, try this:

    <?php
        if(isset($_SESSION['signed_in']) && $_SESSION['user_level'] == 1)
        {
    ?>
        <td>
            <form method="post">
                <input type="hidden" name="hid_catid" id="hid_catid" value="<?php  echo $cat_id; ?>">
                <input type="submit" name="submit" value="Remover" />
            </form>
        <?php
            if(isset($_POST['submit']))
            {
                
$query = "DELETE FROM categories where cat_id = '".(int)$_POST['hid_catid']."'";
mysql_query($query);
            }
        ?>
        </td>
    <?php
    }
    ?>

--> hidden field should have name and id to use

-- Thanks

edited Nov 17, 2023 at 19:30

CommunityBot

11 silver badge

answered Mar 20, 2014 at 12:19

Anand Solanki

3,4254 gold badges19 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

CodeBird Over a year ago

What about injection? Deprecated functions?

VolkerK Over a year ago

Rather unlikely that value="<?= ['cat_id']; ?>" will work. a) using <?= is not recommended and b) what's ['cat_id']. And even worse: this code is prone to sql injections.

VolkerK Over a year ago

sorry, still prone to sql injections. see php.net/manual/en/security.database.sql-injection.php

CodeBird Over a year ago

And you should be telling the OP to stop using deprecated functions, just use (int)$_POST['hid_catid'] this will protect from SQL injection in this case

FrostVolkoff Over a year ago

i did echo the query the only thing that it showed my was "1", thats all, still dont know why the record isnt deleted...

|

Markus Kottländer · Accepted Answer · 2014-03-20 12:35:32Z

0

Your hidden input field needs a name to be accessable after the post. Also I am not sure if ['cat_id'] is the correcty way to reference this variable. Where does it come from?

<form method="post">
    <input type="hidden" name="cat_id" value="<?= $cat_id ?>">
    <input type="submit" name="submit" value="Remover" />
</form>

Then your query has to look like this to correctly grab the id from the post.

mysql_query("DELETE FROM categories where cat_id = " . mysql_real_escape_string($_POST['cat_id']));

edited Mar 20, 2014 at 12:35

answered Mar 20, 2014 at 12:22

Markus Kottländer

8,2844 gold badges42 silver badges61 bronze badges

1 Comment

VolkerK Over a year ago

where cat_id = " . $_POST['cat_id']: prone to sql injections.

Collectives™ on Stack Overflow

PHP Delete record from database MySql

2 Answers 2

8 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

8 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related