So today I ripped my hair (the few that's left) from my head, because my code didn't work as supposed, but no error was shown by my try/catch block, when accessing my database.
So this was the code I worked with:
$dsn = "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME; $dbo = new PDO($dsn, DB_USER, DB_PASS);
and I had to add this, to actually trigger some exceptions: