Hi Nick - thanks for the suggestion. :-) Alas, it does not really work. I get a combinatorial explosion of the rows returned due to the use of multiple joins in the select.
I need some way of instructing NHibernate to load the data using multiple selects, but to send them over the wire in the same statement just like MultiCriteria. It is the round-tripping to the server I want to reduce. I found an example in the NH 1.2 documentation where you could use UniqueResult() on the MultiCriteria to achieve something along those lines, but that method has been removed from NH 2.0. Regards Thomas On 27 Maj, 15:53, Nick Nguyen <[email protected]> wrote: > Try this for I've found you don't need the alias when setting the > fetch mode: > > var criteria = session.CreateCriteria(typeof(A)).Restrictions.IdEq > (id); > criteria.SetFetchMode("Manager.BList", FetchMode.Join); > criteria.SetFetchMode("Manager.BList.CList", FetchMode.Join); > criteria.SetFetchMode("Manager.BList.DList", FetchMode.Join); > > --Nick > > On May 26, 8:16 am, Thomas Koch <[email protected]> wrote: > > > > > Hi Roger - thank you for your reply. :-) > > > I have only tried to use the Criteria API: > > > var criteria = session.CreateCriteria(typeof(A)).Restrictions.IdEq > > (id); > > criteria.SetFetchMode("Manager.BList", FetchMode.Join); > > criteria.CreateAlias("Manager.BList","bl"); > > criteria.SetFetchMode("bl.CList", FetchMode.Join); > > criteria.SetFetchMode("bl.DList", FetchMode.Join); > > criteria.SetResultTransformer(new DistinctRootEntityResultTransformer > > ()); > > > return criteria.UniqueResult<A>(); > > > I had an error when I entered my domain in the first post. It looks > > like this: > > > A > > | > > * > > B -* C > > | > > * > > D > > > So what I am trying to do is load one entity A, including all of its B > > entities. B itself has two associations C and D which must also be > > loaded. > > The loading of C and D is done in separate selects to the database. > > > I will try to use HQL instead of the criteria API and see how it goes. > > > Cheers, > > Thomas > > > On 26 Maj, 13:56, Roger Kratz <[email protected]> wrote: > > > > You want to eager load some entities and their collections using joins on > > > db side? > > > > As you mention, fetchmode.join (or join fetch in hql), should be the way > > > to go. > > > SetFetchMode("SomeCollection", FetchMode.Join) > > > If you have misspelled "SomeCollection" or not using the mapped prop > > > name, you will not get an exception but the statement is ignored. Maybe > > > that's happened to you? > > > > -----Original Message----- > > > From: [email protected] [mailto:[email protected]] On > > > Behalf Of Thomas Koch > > > Sent: den 26 maj 2009 13:40 > > > To: nhusers > > > Subject: [nhusers] Help with optimizing loading of associations > > > > Hello everyone. > > > > I want to optimize the loading of data in my domain model. > > > > In the past I have used MultiCriteria to load data from different > > > tables "in one go" to the database. > > > > However, is it possible to use something similar to MultiCriteria to > > > have NHibernate load an entity and its association in one go? > > > > For instance, if I have a domain model like this: > > > > A -* B -* C > > > | > > > * > > > D > > > > Translation: Entity A has a collection of B and D, and B in turn has a > > > collection of D. > > > > I tried using FetchMode = Join and Fetch for the associations when > > > loading A, but the loading still gives rise to separate selects > > > against the database (at least according to Ayendes NHprofiler). > > > > In theory I could use MultiCriteria to load the data of A, B, C and D > > > as in one go, but as I understand it the instances thus loaded will > > > not be "wired together". So even though all the Bs of A was loaded, > > > doing A.Bs will still cause the B's to be loaded. > > > > Does anyone know if its possible to achieve something similar to the > > > MultiCriteria where NHibernate is still wiring the entities together? > > > > Regards > > > Thomas- Skjul tekst i anførselstegn - > > > > - Vis tekst i anførselstegn -- Skjul tekst i anførselstegn - > > - Vis tekst i anførselstegn - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nhusers?hl=en -~----------~----~----~----~------~----~------~--~---
