In Doctrine 2 can the Fetch Mode (Eager/Lazy etc.)

问题:

I have entities which I would like to eagerly load , and on other ocassions lazy (or even extra lazy) load.

My mappings have no fetch mode declared in my YAML- so they use the default (lazy loading).

Currently the only way to eagerly load is to by constructing the DQL manually - and I need to update this every time I add a new entity.

Ideally I would just load the root entity and the force eager loading all the associated objects. Is there any way I can do this?

If not why (is there a reason beyond it being an unimplemented feature)?

回答1:

If you want to use built-in repository methods (find(), findAll()), you're probably out of luck unless you set things to eagerly load in your annotations.

You'll probably want to use the query builder (or raw DQL) in some custom repository's method to force eager loading where you want it. Yes, you'll have to update that method as you add entities, but at least you'll always know what's going on in regards to lazy/eager loading, and you'll only need to maintain it all in one place.

I suppose the reason there's not some $eagerLoad flag to find(), etc, is because those are convenience methods for simple tasks. If you wanted to add such a flag, you'd have quickly get into situations where you'd want to limit recursive eager loading by depth. You'd also probably have to start worrying about cyclical references (any bidirectional association, for instance).

回答2:

You can use setFetchMode() method of DQL to set mode. See the documentation: http://readthedocs.org/docs/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html#temporarily-change-fetch-mode-in-dql