public static function get_instance()
{
if (isset(self::$db_conn)) {
return self::$db_conn;
} else {
require __DIR__ . '\\config.php';
global $hostname, $username, $password, $dbname;
self::$db_conn = mysqli_connect($hostname, $username, $password);
mysqli_select_db(self::$db_conn, $dbname);
return self::$db_conn;
}
}
