在 Doctrine 2 中更新(从反面)双向多对多关系? [英] Updating (from the inverse side) bidirectional many-to-many relationships in Doctrine 2?

问题描述

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

/**
 * @ORMManyToMany(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'    => 'AcmeHelloBundleEntityKeyword',
    '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 DoctrineORMPersistentCollection, which holds only selected keywords.

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

解决方案

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!

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