Symfony2: Error persisting ManyToMany/OneToMany Relationships - symfony

Question

I don't know why, maybe i am missing some basic logic but I always run again into the same issue. I can't persists ManyToMany collections, and it also faces me with OneToMany collections, though I can work around that.
I read through the doctrine documentation, and I think I do understand the thing with mappedBy and inversedBy (where the last one is always the owner and therefor responsible for persisting the data, please correct me if I am wrong).
So here's a basic example that I have right now, which I can't figure out.
I have an Entity called Site:
#Site.php
...
/**
* #ORM\ManyToMany(targetEntity="Category", mappedBy="sites")
*/
protected $categories;
and another one called Category:
#Category.php
...
/**
* #ORM\ManyToMany(targetEntity="Site", inversedBy="categories")
* #ORM\JoinTable(name="sites_categories")
*/
protected $sites;
Using the Symfony2 entity genenerator it added me some getters and setters to my Entites which look like this.
Site:
#Site.php
...
/**
* Add categories
*
* #param My\MyBundle\Entity\Category $categories
*/
public function addCategory(\My\MyBundle\Entity\Category $categories)
{
$this->categories[] = $categories;
}
/**
* Get categories
*
* #return Doctrine\Common\Collections\Collection
*/
public function getCategories()
{
return $this->categories;
}
The same counts for
Category:
#Category.php
...
/**
* Add sites
*
* #param My\MyBundle\Entity\Site $sites
*/
public function addSite(\My\MyBundle\Entity\Site $sites)
{
$this->sites[] = $sites;
}
/**
* Get sites
*
* #return Doctrine\Common\Collections\Collection
*/
public function getSites()
{
return $this->sites;
}
Fair enough.
Now in my controller, I am trying to persist a Site object:
public function newsiteAction() {
$site = new Site();
$form = $this->createFormBuilder($site); // generated with the FormBuilder, so the form includes Category Entity
// ... some more logic, like if(POST), bindRequest() etc.
if ($form->isValid()) {
$em = $this->getDoctrine()
->getEntityManager();
$em->persist($site);
$em->flush();
}
}
The result is always the same. It persists the Site Object, but not the Category entity. And I also know why (I think): Because the Category entity is the owning side.
But, do I always have to do something like this for persisting it? (which is actually my workaround for some OneToMany collections)
$categories = $form->get('categories')->getData();
foreach($categories as $category) {
// persist etc.
}
But I am running into many issues here, like I would have to do the same loop as above for deleting, editing etc.
Any hints? I will really give a cyber hug to the person who can clear my mind about that. Thanks!
.
.
.
UPDATE
I ended up changing around the relationship (owning and inverse side) between the ManyToMany mapping.
If somebody else runs into that problem, you need to be clear about the concept of bidrectional relationships, which took me a while to understand too (and I hope I got it now, see this link).
Basically what anserwed my question is: The object you want to persist must always be the owning site (The owning site is always the entity that has "inversed by" in the annotiation).
Also there is a concept of cascade annotation (see this link, thanks to moonwave99)
So thanks, and I hope that helps somebody for future reference! :)

Answer 1

Regarding OneToMany relationship, you want to know about cascade annotation - from Doctrine docs [8.6]:
The following cascade options exist:
persist : Cascades persist operations to the associated entities.
remove : Cascades remove operations to the associated entities.
merge : Cascades merge operations to the associated entities.
detach : Cascades detach operations to the associated entities.
all : Cascades persist, remove, merge and detach operations to associated entities.
following docs example:
<?php
class User
{
//...
/**
* Bidirectional - One-To-Many (INVERSE SIDE)
*
* #OneToMany(targetEntity="Comment", mappedBy="author", cascade={"persist", "remove"})
*/
private $commentsAuthored;
//...
}
When you add comments to the author, they get persisted as you save them - when you delete the author, comments say farewell too.
I had same issues when setting up a REST service lately, and cascade annotation got me rid of all the workarounds you mentioned before [which I used at the very beginning] - hope this was helpful.