I need to update a MySql database from inside a JS function within a WordPress Woocommerce page. I’m using Ajax to do this. The following code works fine as a stand-alone code but when I put it into the WordPress page (on my localhost) it throws an error 500. Also I put the required data (which will eventually be a variable) onto the end of the url (?test=14230) because I couldn’t get it to send the data when using the data: line in the Ajax.
Here’s the Ajax:
function db()
{
$.ajax({
url: 'update_db.php?test=14230',
type: 'post',
data: 0,
success: function(output)
{
alert('Success, server says '+output);
}, error: function()
{
alert('Something went wrong.');
}
});
}
Here’s the update_db.php:
<?php
if(isset($_GET['test']) ){
$id = $_GET['test'];
}
include 'database-handler.php';
$sql = "UPDATE db_name SET column = 'Some Value' WHERE id = $id";
if(mysqli_query($conn, $sql)){
//echo ('<p>'."Success.".'</p>');
} else {
//echo ('<p>'."Something went wrong. $sql. " . mysqli_error($conn).'</p>');
}
mysqli_close($conn);
?>
So I’m just wondering why this works as a stand-alone code but not when it’s inside WordPress?
Edit: Here is the error log:
[Wed Nov 09 15:16:47.543162 2022] [php:error] [pid 4564:tid 1828] [client ::1:5888] PHP Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in C:xampphtdocsmy-siteswowcardwp-contentthemesblocksy-childwoocommercesingle-productsave-card-size.php:17nStack trace:n#0 C:xampphtdocsmy-siteswowcardwp-contentthemesblocksy-childwoocommercesingle-productsave-card-size.php(17): mysqli_query(NULL, ‘UPDATE new_card…’)n#1 {main}n thrown in C:xampphtdocsmy-siteswowcardwp-contentthemesblocksy-childwoocommercesingle-productsave-card-size.php on line 17, referer: http://localhost/my-sites/wowcard/product/polka-dot-brush-strokes-two-photo-birthday-card-purple/?card=complete&id=14230
2
Answers
Edit:
I believe the issue I had was due to the Ajax being embedded within more than one WordPress function and also a Woocommerce action. The variable I needed was not being passed from my PHP to the Ajax like it normally would be. I used a session variable instead, which fixed that particular issue.
The Ajax now uses the "data:" line to pass the data over to save-card-size.php rather than passing it inside the url. I would show the code but the editor is too glitchy on this site, it wouldn't allow me to copy and paste my code properly.
I also had to replace the include in save-card-size.php with the contents of database-handler.php.
Everything is now working.
WordPress has its own database handler which is automatically loaded, there are most likely conflicts between your code and WordPress, but without seeing the actual error, I can not give more information.
Check this out https://developer.wordpress.org/reference/classes/wpdb/
Example: