Difference between ObjectManager and EntityManager in Symfony2?
doctrine, doctrine-orm, symfony, symfony-forms
Solution
`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.
Problem
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; } } ```