Question

I have an Article and Comment entity (oneToMany)

On Comment prepersist lifecycle event I would like to count how many comments there are for this article and update Article’s comment_count field.

If I understand symfony2 approach correctly, I need to write a service for this. Let’s call it CommentCountManager.

My question is: How exactly do I make container available in entity so that I can get the CommentCountManager and triger the funciton that count comment for given article, and how do I access Doctrine’s entity manager in my CommentCountManager so that I can actually run queries there?

Am I on the right path?

Your help is greatly appreciated.

Answer 1

You don’t need to store the comments count in a separate column — you can count them on output. What you are trying to do is denormalization and I recommend avoiding it unless you absolutely need it for performance reasons — and only when you are sure that that part is causing the problems. But even then, query optimization and caching are much better alternatives to denormalization.

Making entities aware of the container is a bad idea too. If you need this, then you are doing something wrong.

To access an entity manager in a service, you need to inject it.