An optional OneToOne relationship between entities? - symfony

Question

I have a User Entity. This is considered the primary entity in this case and the mere fact it is being used means it is present.
The User entity, has a Store entity. But not all Users will necessarily have a Store entity.
It is worth noting that this is an existing database we are working with, and the id for the User table is the same as the id for the Store table. Name (id) and Value. It's just that in some cases, Store does not have a record for a given User id.
User:
class User extends Entity
{
/**
* #ORM\Id
* #ORM\Column(type="string", length=36)
*/
protected $id;
/**
* #ORM\OneToOne(targetEntity="Store")
* #ORM\JoinColumn(name="id", referencedColumnName="id")
*/
protected $store;
...
}
Store:
class Store extends Entity
{
/**
* #ORM\Id
* #ORM\Column(type="string", length=36)
*/
protected $id;
...
}
This causes problems in the controllers. If a User entity does not have a Store record, it fails with a "Entity not found" exception. This can be dealt with using a try catch easy enough (I haven't been able to find a way to check if an Entity object exists or is just a proxy). If the User does have a store record, all is fine here.
But the big issue I have is especially the Fixtures:
protected function createUser($id)
{
$user = new User();
$user->setId($id);
$user->setEmail($id.'#example.com');
$user->setUserName($id.'_name');
$user->setArea($this->manager->find('Area', 156)); // Global
$this->manager->persist($user);
return $user;
}
When I run Fixtures, this fails. Giving me the error "Integrity constraint violation: 1048 Column 'id' cannot be null". This message disappears if I remove the store entity from User. So in a nutshell, I cannot add a user if it doesn't have a store.
Anyone know what's happening? I've done some looking around and I can't find anything, including doctrine docs, on having optional relationships between Entities. Which I thought would have been a common situation.

Answer 1

Found the solution to this on this doc page:
http://docs.doctrine-project.org/en/latest/tutorials/composite-primary-keys.html#use-case-3-join-table-with-metadata
In my case, rather than the User entity being associated with the Store entity using the id field, the store property in the User entity would be associated to the Store entity by user (an entity object). In return, the Store object will hold a User entity, which is annotated as the entity's id.
I'm sure that's as confusing as hell, so just look at the sample above. Below are my adjusted Entity classes:
User
class User extends Entity
{
/**
* #ORM\Id
* #ORM\Column(type="string", length=36)
*/
protected $id;
/**
* #ORM\OneToOne(targetEntity="Store", mappedBy="user")
*/
protected $store;
...
}
Store
class Store extends Entity
{
/**
* #ORM\Column(type="string", length=36)
*/
protected $id;
/**
* #ORM\Id
* #ORM\OneToOne(targetEntity="User")
* #ORM\JoinColumn(name="id", referencedColumnName="id")
*/
protected $user;
...
}
Now, if there is no Store record present for a given User, the store property in the User entity will be null. Fixtures runs as expected too.

Answer 2

In addition to the answer above, I also needed to add an inversedBy attribute. Otherwise, an invalid Entity mapping error will be thrown.
Using the entities above, the Store object would need to look like this:
class Store extends Entity
{
/**
* #ORM\Column(type="string", length=36)
*/
protected $id;
/**
* #ORM\Id
* #ORM\OneToOne(targetEntity="User", inversedBy="store")
* #ORM\JoinColumn(name="id", referencedColumnName="id")
*/
protected $user;
...
}