... their attributes of type collection in ONE query in case of classes hierarchy?

For example:
There is a base Class B, and derived classes D1, D2, D3.

I want get all objects inherited from B with HQL query:
FROM B

How can I say to NHibernate to retrieve all objects of inherited class with their attributes of type collection in one HQL query?

I use Hiberante version 2.x

Best regards,
Sergey

NHibernate, you mean the .net version? 'N' is close to 'H' on the keyboard ;-)

I'm not sure I understand your question. "FROM B" is going to return D1s and D2s .

I use NHibernate and previously a posted this message to NHibernate forum but was not answered.

Yes, you are right.
"FROM B" is going to return D1s and D2s

But I don't know how to encourage Hibernate to
load all collections (sets, bags and so on) that are in D1 and
D2 classes in THE SAME QUERY.

All collections are lazy but I want not turn lazy mode off.

I just want to load entire objects of classes inherited form B in
ONE query and only in THAT query.