Hibernate version: 1.2.0 GA

Name and version of the database you are using: MS SQL 2000

I have a class (A) with a collection of children (B), which also has a collection of children (C). I would like to load this entire object graph, ie. all instances of A with all child instance B and all grandchild instances C as quickly as possible. Collections of B and C are mapped as bags and are not lazy-loaded.

Currently I'm loading them using code like this:

Session.CreateQuery("from A").List<A>()

This works fine for A, but it then runs a separate queries to load entities B and C for each instance of A. I believe it should be considerably faster to load all instances of A, all instance of B and all instances of C (3 queries in total) and then put them into the appropriate collections. Is there a way to do this with NHibernate? Alternatively, can I write the code to do this myself, but in such a way that NHibernate knows that all the collections have been loaded and does not try to load them again?

The docs on fetching strategy here should have all your answer:
http://www.hibernate.org/hib_docs/nhibe ... e-fetching

If you can live with three queries instead of one, sub-select fetching may be your answer. Read the docs for more details.

Thanks very much! fetch="subselect" does the trick. I've found I also had to call Session.Evict() on all instances of A and set cascade="all" for A->B and B->C bags, otherwise NHibernate tries to flush all the loaded entities, which wastes quite a bit of time.