doctrine-l2-example.php

<?php

$user = new User();
$user->setName('John Doe');

// put user to cache
$entityManager->persist($user);
$entityManager->flush();
$entityManager->clear();

unset($user);

// load user from the cache
// avoid database call
$user = $entityManager->find(User::class, 1);

// create a new post
$post = new Post();
$post->setTitle('Awesome title');

$user->addPost($post);

$entityManager->persist($post);
$entityManager->flush();
$entityManager->clear();

// load user posts from the cache
// avoid database call

foreach ($user->getPosts() as $post) {
    echo $post->getTitle();
}