Doctrine entity remove vs delete query, performance comparison

Question

While using doctrine, I noticed that, to delete an entity, I need to retrieve that entity by given parameter(name,id etc) and then call the remove method. On the other hand, in query, I can just execute delete query.

So, seems like, using ORM style requires two operation and general sql operation require one operation. That's why, I am a little confusing, whether we should use delete(or update) operation in ORM? Isn't it worse in performance? Or Is there anything else I am missing? Can it be done in any other way in ORM style?

Answer 1

In Doctrine2 you can call the delete on a proxy object, which is not loaded from the database. Just create a "dummy" object, something like:

$user = $em->getPartialReference('model\User', array('id' => $id));
$em->remove($user);

It doesn't require the initial query, but I'm not quite sure if Doctrine still does it internally on flush. I don't see it in the SqlLog.

Just to add, I think this is expected behavior of any decent ORM. It deals with objects and relations. It has to know that something exists before deleting it. ORM is not just a query generator. Generally, a native query will always be faster in any ORM. Any ORM adds a layer of abstraction and it takes some time to execute it. It is a typical tradeoff, you get some fancy features and clean code, but loose some on performance.

EDIT:

I'm glad it worked out for you. Actually I stumbled on another problem, which made me realize that proxies and partial objects aren't actually the same thing. Partial objects instance the real model class, and fill it with values you want. After you initialize a partial object lazy-loading doesn't work on it anymore. So for instance, if you make a partial object with only the id, and want to delete only if another object field satisfies some condition, it will not work, because that other field will always be null.

On the other hand, proxies do work with lazy-loading, and don't share the problems that partial objects have. So I would strongly suggest not to use getPartialReference method, instead you can do something like:

$user = $em->getReference('model\User', $id);
$em->remove($user);

The getReference method returns the object if it is already loaded or a proxy if it is not. A proxy can lazy-load all the other values if/when you need them. As for your example, they will behave exactly the same, but proxies are surely a better way to go.

Answer 2

Done! for me it worked like this add line 3:

$user = $em->getReference('model\User', $id);
$em->remove($user);
$em->flush();