Online PHP editor | refs for R15m0

<?php if (isset($_POST['submit']) && isset($_POST['titel']) && isset($_POST['trainer']) && isset($_POST['dauer']) && $_POST['titel']&& isset($_POST['datum']) && isset($_POST['ort']) != '' && $_POST['trainer'] != '' && (int)$_POST['dauer'] > 0) { try { $db = new MySQLi('localhost', 'root', '', 'php5_db_test'); echo 'Verbindung offen.<br />'; $sql = 'INSERT INTO trainings (titel, trainer, dauer, datum, ort) VALUES (?, ?, ?, ?, ?)'; $kommando = $db->prepare($sql); $kommando->bind_param('ssiss', $_POST['titel'], $_POST['trainer'], (int)$_POST['dauer'], $_POST['datum'], $_POST['ort']); $kommando->execute(); echo 'SQL geschickt.<br />'; $db->close(); echo 'Verbindung zu.<br />'; } catch (Exception $e) { echo 'Fehler: ' . htmlspecialchars($e->getMessage()); } } ?>