Symfony2/Doctrine2.1: Persisting OneToOne relations with simple derived identity

Question

I am trying to persist an user entity with a profile entity from a single form submit. Following the instructions at the Doctrine2 documentation and after adding additional attributes this seemed to be sufficient to achieve the goal.

Entities

Setting up the entites in accordance is pretty straight forward and resulted in this (I left out the generated getter/setter):

// ...

/**
 * @ORM\Entity
 */
class User
{
  /**
   * @ORM\Id
   * @ORM\Column(type="integer")
   * @ORM\GeneratedValue
   */
  private $id;

  /**
   * @ORM\Column(type="string", length=64)
   */
  private $data;

  /**
   * @ORM\OneToOne(targetEntity="Profile", mappedBy="user", cascade={"persist", "remove"})
   */
  private $Profile;

  // ...
}

// ...

/**
 * @ORM\Entity
 */
class Profile
{
  /**
   * @ORM\Id
   * @ORM\OneToOne(targetEntity="User")
   */
  private $user;

  /**
   * @ORM\Column(type="string", length=64)
   */
  private $data;

  // ...
}

Forms

Now modifiying the forms is not too difficult as well:

// ...

class ProfileType extends AbstractType
{
  public function buildForm(FormBuilder $builder, array $options)
  {
      $builder
          ->add('data')
      ;
  }

  public function getName()
  {
      return 'profile';
  }

  public function getDefaultOptions(array $options)
  {
      return array('data_class' => 'Acme\TestBundle\Entity\Profile');
  }
}

// ...

class TestUserType extends AbstractType
{
  public function buildForm(FormBuilder $builder, array $options)
  {
      $builder
          ->add('data')
          ->add('Profile', new ProfileType())
      ;
  }

  public function getName()
  {
      return 'user';
  }
}

Controller

class UserController extends Controller
{
  // ...

  public function newAction()
  {
      $entity = new User();
      $form   = $this->createForm(new UserType(), $entity);

      return array(
          'entity' => $entity,
          'form'   => $form->createView()
      );
  }

  public function createAction()
  {
      $entity  = new User();
      $request = $this->getRequest();
      $form    = $this->createForm(new UserType(), $entity);
      $form->bindRequest($request);

      if ($form->isValid()) {
          $em = $this->getDoctrine()->getEntityManager();
          $em->persist($entity);
          $em->flush();

          return $this->redirect($this->generateUrl('user_show',
              array('id' => $entity->getId())));

      }

      return array(
          'entity' => $entity,
          'form'   => $form->createView()
      );
    }

    // ...
}    

But now comes the part where testing takes place. I start to create a new user-object, the embedded form shows up as expected, but hitting submit returns this:

Exception

Entity of type Acme\TestBundle\Entity\Profile is missing an assigned ID. The identifier generation strategy for this entity requires the ID field to be populated before EntityManager#persist() is called. If you want automatically generated identifiers instead you need to adjust the metadata mapping accordingly.

A possible solution I am already aware of is to add an additional column for a stand-alone primary key on the Profile entity.

However I wonder if there is a way to keep the mapping roughly the same but deal with persisting the embedded form instead?

Answer 1

After debating for quite a while with a couple of people via IRC I modified the mapping and came up with this:

Entities

// ...

/**
 * @ORM\Entity
 */
class User
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @ORM\Column(type="string", length=64)
     */
    private $data;

    /**
     * @ORM\OneToOne(targetEntity="Profile", cascade={"persist", "remove"})
     */
    private $Profile;

    // ...
}

// ...

/**
 * @ORM\Entity
 */
class Profile
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\Column(type="string", length=64)
     */
    private $data;

    // ...

}    

So what does this change? First of all I removed the mappedBy and inversedBy options for the relation. In addition the OneToOne annotation on the Profile-entity was not needed.

The relation between User and Profile can be bi-directional however a uni-directional relation with User being the owning side is sufficient to have control over the data. Due to the cascade option you can be sure there are no left-over Profiles without Users and Users can maintain a Profile but do not have to.

If you want to use a bi-directional relation I recommand taking a look at Github: Doctrine2 - Tests - DDC117 and especially pay attention to Article and ArticleDetails' OneToOne relation. However you need to be aware that saving this bi-directional relation is a bit more tricky as can be seen from the test file (link provided in comment): you need to persist the Article first and setup the constructor in ArticleDetails::__construct accordingly to cover the bi-directional nature of the relationship.

Answer 2

The problem from what I can see is that you're only creating / saving a User object.

As the User / Profile is a One to One relation (with User being the owning side) would it be safe to assume that a User will always have a Profile relation, and so could be initialised in the Users construction

class User 
{
    public function __construct()
    {
        $this->profile = new Profile();
    }
}

After all you've set User up to cascade persistence of the related Profile object. This will then have your entity manager create both Entities and establish the relation.