保存相关实体学说/ Symfony2

Question

I have one specific issue. I have two entities:

    class MyPlaylist {
   ...
    /**
     * @var Array 
     * @ORM\OneToMany(targetEntity="MyPlaylistContent", mappedBy="myPlaylist", orphanRemoval=true)
     * @ORM\OrderBy({"position" = "DESC"})
     */
    private $myPlaylistItems;

and

class MyPlaylistContent {
....

    /**
     * @ORM\ManyToOne(targetEntity="MyPlaylist", inversedBy="myPlaylistItems")
     */
    private $myPlaylist;

Now I have this in my service

....    
    $myPlaylist = new MyPlaylist();
    $myPlaylist->setUser($user);
    $myPlaylist->setActive(true);

    // add tracks
    foreach ($playlist->getMyPlaylistItems() as $item) {
      $entity = new MyPlaylistContent();
      $entity->setTrack($item->getTrack());
      $entity->setMyPlaylist($myPlaylist);
      $this->em->persist($entity);
    }

    $this->em->persist($myPlaylist);
    $this->em->flush();

    \Doctrine\Common\Util\Debug::dump($myPlaylist);

    return $myPlaylist;

so, I return a new playlist. If I look at the database, all works fine. I have both entities and in MyPlaylistContent - 3 tracks. But

\\Doctrine\\Common\\Util\\Debug::dump($myPlaylist); shows next

["active"]=> bool(true) ["myPlaylistItems"]=> array(0) { }

On the page, the app shows the empty playlist (no tracks). If I refresh the page, I can see all tracks.

The point is, if you open the page, the controller will call the service, build the content and return the list as a response. It looks as the same example, but it does not work for me http://symfony.com/doc/current/book/doctrine.html#saving-related-entities

What is wrong here? Why don't I get tracks for the current entity?

Answer 1

You forget to add MyPlaylistContent to MyPlaylist .

Use this snippet into foreach

$myPlaylist->addMyPlaylistContent($myPlaylistContent);

Of course change name or implement method accordingly

First note: this is because objects are "normal" php objects, they have nothing to do with doctrine so, relationships are only a doctrine concept. EntityManager in doctrine will handle this kind of processes, not php itself. If you take a look to your classes methods you will probably notice that no "connection" (assignments) are made between those objects. If you would like, you can modify MyPlaylistContent to add itself to MyPlaylist once assigned. Something like

class MyPlaylistContent { [...]

public function setMyPlaylist(MyPlaylist $mp) 
{
    $this->myPlaylist = $myPlaylist;
    $mp->addMyPlaylistContent($this);

    return $this;
}

Second note: hope your names are more consistents of these ones :)