Updating (from the inverse side) bidirectional many-to-many relationships in Doctrine 2?

Question

Customer is the inverse side of "keywords/customers" relationship with Keyword:

/**
 * @ORM\ManyToMany(targetEntity="Keyword", mappedBy="customers",
 *     cascade={"persist", "remove"}
 * )
 */
protected $keywords;

When creating a new customer, one should select one or more keywords. The entity form field is:

$form->add($this->factory->createNamed('entity', 'keywords', null, array(
    'class'    => 'Acme\HelloBundle\Entity\Keyword',
    'property' => 'select_label',
    'multiple' => true,
    'expanded' => true,
)));

In my controller code, after binding the request and check if form is valid, I need to persist both the customer and all customer/keyword(s) associations, that is the join table.

However customer is the inverse side, so this is not working:

if($request->isPost()) {
    $form->bindRequest($request);

    if(!$form->isValid()) {
        return array('form' => $form->createView());
    }

    // Valid form here   
    $em = $this->getEntityManager();

    $em->persist($customer);    
    $em->flush();
}

Event with "cascade" option, this code fails. $customer->getKeywords() will return Doctrine\ORM\PersistentCollection, which holds only selected keywords.

Should I manually check which keyword was removed/added and then update from the owning side?

Answer 1

Ok, found the way, even if I'm not fully satisfied. The key was this example form collection field type. Basically what's happening with my previous form definition was:

$customer->getKeywords() = $postData; // $postData is somewhere in form framework

And that is just an assignment of a collection (of selected keywords) to customer keywords. No method were invoked on Keyword instances (owning side). The key option is by_reference (for me it's just a bad name, but anyways...):

$form
    ->add($this->factory->createNamed('entity', 'keywords', null, array(
        // ...
        'by_reference' => false
    ))
);

This way the form framework is going to call the setter, that is $customer->setKeywords(Collection $keywords). In that method, you can "tell" the owning side to store your association:

public function setKeywords(Collection $keywords)
{
    foreach($keywords as $keyword) {
        $keyword->addCustomer($this); // Owning side call!
    }

    $this->keywords = $keywords;

    return $this;
}

(Always check for duplicate instances on the owning side, using contains method).

At this point, only checked keywords will be added ($keyword argument). There is the need to manage removal of unchecked keywords (controller side):

$originalKeywords = $customer->getKeywords()->toArray(); // When GET or POST

// When POST and form valid
$checkedKeywords = $customer->getKeywords()->toArray(); // Thanks to setKeywords

// Loop over all keywords
foreach($originalKeywords as $keyword) {
    if(!in_array($keyword, $checkedKeywords)) { // Keyword has been unchecked
        $keyword->removeCustomer($customer);
        $manager->persist($keyword);
    }
}

Ugly, but works. I would have the code for removal moved to the Customer class, but it's not possible at all. If you'll find a better solution, let me know!

Answer 2

I use slightly different solution than @gredmo. From doctrine documentation: you can use Orphan Removal when you satisfy this assumption:

When using the orphanRemoval=true option Doctrine makes the assumption that the entities are privately owned and will NOT be reused by other entities. If you neglect this assumption your entities will get deleted by Doctrine even if you assigned the orphaned entity to another one.

I have this entity class:

class Contract {
/**
 * @ORM\OneToMany(targetEntity="ContractParticipant", mappedBy="contract", cascade={"all"}, orphanRemoval=true)
 **/
}
protected $participants;

form processing (pseudo code):

    // $_POST carry the Contract entity values

    $received = [];

    foreach ($_POST['participants'] as $key => $participant) {

        if ((!$relation = $collection->get($key))) {
            // new entity
            $collection[$key] = $relation = $relationMeta->newInstance();

        } else {
            // editing existing entity
        }

        $received[] = $key;
        $this->mapper->save($relation, $participant);   // map POST data to entity
    }

    foreach ($collection as $key => $relation) {
        if ($this->isAllowedRemove() && !in_array($key, $received)) {
            // entity has been deleted
            unset($collection[$key]);
        }
    }

Don't forget to persist the entity end flush. Flush also deletes the removed entities.

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