Doctrine 2.1 - Relation Lost After ManyToMany Casc

Question

After merging an entity that has related entities with relations set to cascade both persist and merge operations the relations are lost!

Here are the entities:

class Event implements NormalizableInterface
{
    /**
     * @ORM\ManyToMany(targetEntity="Participant", inversedBy="events", cascade={"persist", "merge"})
     * @ORM\JoinTable(name="event_participant",
     *      joinColumns={@ORM\JoinColumn(name="event_id", referencedColumnName="id", onDelete="CASCADE")},
     *      inverseJoinColumns={@ORM\JoinColumn(name="participant_id", referencedColumnName="id", onDelete="CASCADE")}
     *      )
     */
    private $participants;
}


class Participant implements NormalizableInterface
{
    /**
     * @ORM\ManyToMany(targetEntity="Event", mappedBy="participants", cascade={"persist", "merge"})
     */
    protected $events;
}

Here are my joins:

foreach ($events as $event)
{
    if (!$event->hasParticipant($participant)) {

        $event->addParticipant($participant);
    }
    if (!$participant->hasEvent($event)) {

        $participant->addEvent($event);
    }
}

Here is my merge code:

echo "Before merge participant count: ".count($event->getParticipants()).PHP_EOL;

$event = $em->merge($event);

echo "After merge participant count: ".count($event->getParticipants()).PHP_EOL;

...and here is the output:

Before merge participant count: 2
After merge participant count: 0

..and the database looks like this:

table               | rows
-------------------------------
event               | 1
-------------------------------
participant         | 2
-------------------------------
event_participant   | 0
-------------------------------

Can anyone see where I'm being dumb?

BTW there are more relationships than this. I've simplified things here to make the explanation clearer. My other relations aren't affected negatively by the merge. Also I'm doing the merge in a console Command not a in a controller. I can post more code if it'll help :)

Also I'm using Doctrine 2.1.7 and Symfony 2.0.15

Many thanks, Matthew

Answer 1

i found the same problem and after think some minutes i tried a simple think, just change code order and treat the merged as new instance of the entity, i figure out that the merge action can be removing the relations, so:

$user = new User();
$user->setName('name');
$user->setAge('24');

$mergedUser = $em->merge($user);

// Imagine we have some groups to add
foreach ($groups as $group) {
    $mergedUser->addGroup($group);
}

$em->flush();

Its works for me.

I hope it helps.

Answer 2

Is this issue not related to your merge: http://doctrine-orm.readthedocs.org/en/2.0.x/reference/limitations-and-known-issues.html#cascade-merge-with-bi-directional-associations?

Answer 3

I've faced the same issue, and fixed it by refreshing the entity after merge:

$mergedEntity = $entityManager->merge($serializedEntity);
$entityManager->refresh($mergedEntity);