Simplify the Doctrine query - mysql

Question

I am new to Doctrine ORM or any ORM
$em = Zend_Registry::getInstance ()->entitymanager;
$p = $em->createQuery ( "
SELECT u
FROM Teon_Model_User u
WHERE u.app_auth IN (:app_auth)" );
$p->setParameter ( 'app_auth', $app_auth );
$array = $p->getArrayResult();
$customer_id = $array[0]['customer_id'];
$p = $em->createQuery ( "
SELECT p
FROM Teon_Model_Purchase p
WHERE p.customer IN (:customer_id)" );
$p->setParameter ( 'customer_id', $customer_id );
$array = $p->getArrayResult();
$purchase_id = $array[0]['id'];
$p = $em->createQuery ( "
SELECT pm
FROM Teon_Model_PurchaseManual pm
WHERE pm.purchase_id IN (:purchase_id)" );
$p->setParameter ( 'purchase_id', $purchase_id );
$array = $p->getArrayResult();
$m_id = $array[0]['manual_id'];
Can you simplify this query, it looks so stupid, I am using Doctrine in zend framework
this query is to authenticate the user whether he has manual_id in his purchases by supplying a authentication code..

Answer 1

Here's the 2 simple way i could think of to do this:
<?php
$em = Zend_Registry::getInstance()->entitymanager;
// 1st way
$user = $em->getRepository('Teon_Model_User')->findOneByAppAuth($app_auth);
$user->getCustomerId();
// 2nd way
$user = $em->getRepository('Teon_Model_User')->findOneBy(array(
'app_auth' => $app_auth,
));
$user->getCustomerId();