How to update a database with +1

Question

I would like that for "salade", when I click on the button "+" It add me +1 on my stock.

For example, I have a 25 salade available, When I click on "+" I have now 26 salades,

Here my code:

<?php
if(isset($_POST['stock'])){
    $stock = $_POST['stock'];
    $stock = $stock +1;
}
?>

<?php $req=$db->prepare("UPDATE ingredients SET stock =:stock WHERE nom = 'salade'");
                    $req->execute(array('stock' =>$stock));

I'm not certain if this is what you're asking, but are you looking for `UPDATE ingredients SET stock = stock + 1 ...` ? — iainn, Apr 14 '20 at 10:20
Do you mean `=:stock` should be `= {$stock}`? Also see https://stackoverflow.com/questions/60174/how-can-i-prevent-sql-injection-in-php — Zoe Edwards, Apr 14 '20 at 10:21
it's a placeholder and that's just right @ThomasEdwards. Using your example the code will be susceptible to SQL injection — jrswgtr, Apr 14 '20 at 10:22

A l w a y s S u n n y · Answer 1 · 2020-04-14T10:26:34.043

2

When you click on the "+" button, It adds +1 on your current stock, So you can update it with the current value like stock = stock + 1,

<?php 
$nom = 'salade';
$req=$db->prepare("UPDATE ingredients SET stock = stock + 1 WHERE nom =:nom");
$req->execute(array('nom' =>$nom));
?>

edited Apr 14 '20 at 10:26

answered Apr 14 '20 at 10:22

1

It works but it puts me not +1 but +8 always, it 's probably because I have 8 elements ( salade,tomatoes,...... ) – jacques Apr 14 '20 at 10:26
@jacques if it adds 8 and you say you have 8 elements, that gives me the feeling that there is something wrong in your client side code that triggers this PHP script 8 times. Can you show us your JavaScript code that gets executed when you click on "+1" button. – Accountant م Apr 14 '20 at 12:43
yes , it's good it works now, thx !! But I would like know, Why when I do F5 it refresh me the page, but It add me too +1 ??? – jacques Apr 14 '20 at 13:14

1 Answers1