Difference between ObjectManager and EntityManager in Symfony2?
What's the difference between Doctrine\Common\Persistence\ObjectManager
and Doctrine\ORM\EntityManager
when using it in a custom form type?
I can get the respository using both $this->em->getRepository()
and $this->om->getRepository()
.
class MyFormType extends \Symfony\Component\Form\AbstractType
{
/**
* @var Doctrine\ORM\EntityManager
*/
protected $em;
public function __construct(Doctrine\ORM\EntityManager $em)
{
$this->em = $em;
}
}
Instead of:
class MyFormType extends \Symfony\Component\Form\AbstractType
{
/**
* @var Doctrine\Common\Persistence\ObjectManager
*/
protected $om;
public function __construct(Doctrine\Common\Persistence\ObjectManager $om)
{
$this->om = $om;
}
}
ObjectManager
is an interface and EntityManager
is its ORM implementation. It's not the only implementation; for example, DocumentManager
from MongoDB ODM implements it as well. ObjectManager
provides only the common subset of all its implementations.
If you want your form type to work with any ObjectManager
implementation, then use it. This way you could switch from ORM to ODM and your type would still work the same. But if you need something specific that only EntityManager
provides and aren't planning to switch to ODM, use it instead.