After getting a great response from @majick I was able to resolve an issue I was having with trying to access wp-config.php from a plugin. I've set up the connection file I'm using in the plugin in as so:

function find_require($file,$folder=null) {

    if ($folder === null) {$folder = dirname(__FILE__);}

    $path = $folder.'/'.$file;

    if (file_exists($path)) {require($path); return $folder;}
    else {
        $upfolder = find_require($file,dirname($folder));
        if ($upfolder != '') {return $upfolder;}

$configpath = find_require('wp-config.php');

$conn = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD);
mysqli_select_db($conn, DB_NAME);

With that in place I can load my table content, but when it comes to modifying the table content I've run into an issue. The table is updated, but I get the following errors:

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in ...\wp-content\plugins\editdb\editdatabase.php on line 145

Warning: mysqli_error() expects parameter 1 to be mysqli, null given in ...\wp-content\plugins\editdb\editdatabase.php on line 150

Error getting tables:

Warning: mysqli_close() expects parameter 1 to be mysqli, null given in ...\wp-content\plugins\editdb\editdatabase.php on line 175

As well when the page reloads with the dropdown selection list the list is now empty and does not contain any Employee names from the Database.

I know its related to having this executed in a plugin rather then the theme, but I don't know enough to determine exactly why the null values are occurring.

To put some perspective before using this I had hard coded the wp-config information in the plugin's connect.php file and everything worked, but for obvious reasons that is not best practice.


You should never have to read wp-config to get database credentials. WordPress has built-in functions which are generally more secure for this sort of operation.

In your plugin, simply call global $wpdb;

and you will be connected to the WP database. You can then perform whatever queries you need - select, update, add, etc. For example:

$results = $wpdb->get_results( 'SELECT * FROM wp_options WHERE option_id = 1', OBJECT );

Please see https://codex.wordpress.org/Class_Reference/wpdb for details. This should be both safer and much easier than reading in credentials and manually connecting.

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