Database query is not updating

Question

My database is not updating when I click the submit button.

Here is the code (I already have the database connection code):

<?php
if(isset($_POST['submit']))
{
$product_add=$_POST['product_add'];
$add_item=$_POST['add_item'];

$get = mysql_query("SELECT * FROM stock WHERE item='$product_add'");
$row = mysql_fetch_array($get);

$qty_left = $row['qty_left'];
$qty = $add_item + $qty_left;

mysql_query("UPDATE stock SET qty_left='$qty' WHERE item='$product_add'") or        die(mysql_error());
}


?>

[Please, don't use `mysql_*` functions in new code](http://bit.ly/phpmsql). They are no longer maintained [and are officially deprecated](https://wiki.php.net/rfc/mysql_deprecation). See the [red box](http://j.mp/Te9zIL)? Learn about [*prepared statements*](http://j.mp/T9hLWi) instead, and use [PDO](http://php.net/pdo) or [MySQLi](http://php.net/mysqli) - [this article](http://j.mp/QEx8IB) will help you decide which. If you choose PDO, [here is a good tutorial](http://j.mp/PoWehJ). **You are also wide open to [SQL injections](http://stackoverflow.com/q/60174)** — John Conde, Apr 05 '14 at 16:05
Is your submit button named? I.e.: `name="submit"` and all form elements are indeed named? If your submit button isn't named, nothing will happen because everything first revolves around that conditional statement. Show your HTML form to be certain. `name="Submit"` and `name="submit"` are **two different animals** altogether. `A!=a;` — Funk Forty Niner, Apr 05 '14 at 16:06
I see no syntax error (excluding your table column names of course), so I guess either your `if` condition is not getting executed or your `where` clause in the update statement isn't matching any rows — asprin, Apr 05 '14 at 16:07
Also, if your DB connection is `mysqli_*` based, then another reason why your query will fail. If your DB is `mysqli_*`, then that function and `mysql_*` functions do not mix together. Show full code. There are too many things that can go wrong, and I mean **TOO many.** — Funk Forty Niner, Apr 05 '14 at 16:11
@asprin i don't have any if conditions but i have a row named item — user3501563, Apr 05 '14 at 16:19
Product Name
"; while ($select_query_array= mysql_fetch_array($select_query_run) ) { echo ""; } echo "
"; ?> — user3501563, Apr 05 '14 at 16:23
@Fred-ii- here is the DB Connection mysql_connect('localhost', 'root') or die(mysql_error()); mysql_select_db('dbproject') or die(mysql_error()); — user3501563, Apr 05 '14 at 16:25
(Once you've edited those updates into your question, please delete the comments to keep the question clear for future readers. Thanks) — halfer, Apr 05 '14 at 18:02

score 1 · Answer 1 · edited Apr 05 '14 at 20:28

So many possible reasons:

Is the update query being executed at all? In other way, is isset($_POST['submit']) true ? (in addition to the type attribute, you should have the name="submit" in the submit button for it to work. Unless one of your fields' name is actually "submit" which I doubt)
Is your connection working? var_dump($row); should answer your question
There's a config variable called autocommit normally set to 1. If not, you would have to mysql_query('COMMIT'); everytime you want to save changes to the database. Try adding mysql_query('SET autocommit=1'); ... who knows?

Also, always escape/cast your variables! And also you can get rid of the first query.

<?php
if(isset($_POST['submit']))
{
    $product_add = addslashes($_POST['product_add']);
    $add_item    = (int)$_POST['add_item'];

    mysql_query("UPDATE stock SET qty_left = qty_left + $add_item 
                 WHERE item='$product_add'") 
            or die(mysql_error());
}    
?>

score 0 · Answer 2 · answered Apr 05 '14 at 16:06

0

Try to var_dump your query and execute it on phpMyAdmin: if it works, probably your mysql_connect has wrong access data

answered Apr 05 '14 at 16:06

score 0 · Answer 3 · edited May 23 '17 at 11:57

0

As per what you left for (form-related) code in a comment

In your echo "<select name='product_add' class='form-control'>"; you need to add type="text".

Change it to:

echo "<select name='product_add' type="text" class='form-control'>";

This will affect your query.

edited May 23 '17 at 11:57

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answered Apr 05 '14 at 16:54

Funk Forty Niner

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Database query is not updating

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