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NHibernate: How to fetch an object without its child collections?

Answer 1

A:

When you map the collection, are you specifying not to use lazy loading? Try specifying lazy loading at this point.

David M 2010-01-13 12:23:10

I did not specify anything, so default values apply, however I don't know what is a default value.BTW, problem is "solved". I'll add a comment in a few minutes.

wysek 2010-02-23 11:14:18

Answer 2

A:

We had the same problem in our current solution and setting Lazy in the mapping didn't work. We had to set default-lazy to true and suddenly it worked.

This would work best if all relations should be lazy by default.

Henning 2010-01-13 12:25:07

Ok, I've set Lazy=true on the HasMany attribute and now it works,but in other (more frequent) use-cases I need eager loading...I would prefer to have eager loading by default and lazy on demand,but if that's too complicated... I'll try fixing those other use-cases (now I get LazyInitializationException ... failed to lazily initialize a collection of role ... no session or session was closed)

wysek 2010-01-13 13:08:12

You get that exception because your session has been closed, like the message says. You need to inject your session into your repository/dataaccess class and control the session lifetime from the outside.You'd want the session to last the entire request lifetime, especially if you have lazy loading.We use a UnitOfWork attribute on our mvc controllers to initiate and close down a session, and if any nhibernate exceptions are thrown, it is cought and session is rolled back

Henning 2010-01-13 13:30:44

Answer 3

A:

When using the ICriteria API to retrieve your entities, you can specify (override) the fetchmode that has to be used for the associations:

ICriteria crit = session.CreateCriteria (typeof(MyEntity));
crit.SetFetchMode ("someAssociationPath", FetchMode.Lazy);

Frederik Gheysels 2010-02-22 14:04:33

I've tried that. Have you actually read my question? ;)BTW, problem is "solved". I'll add a comment in a few minutes.

wysek 2010-02-23 11:12:01

Answer 4

A:

It seems to me that you are using one-to-one mapping. In this case lazy loading will not work by design. If it's so please check this article. Otherwise please provide a bit more code and mappings.

zihotki 2010-02-22 14:21:10

Why does it seem to you as a one-to-one mapping? when Object1 has List<Children1> I think it is clear that it is at least one-to-many.BTW, problem is "solved". I'll add a comment in a few minutes.

wysek 2010-02-23 11:13:43

@wysek, you didn't provided any code so I just assumed the most likelihood reason from my point of view. Sorry, I'm not well at mind reading.

zihotki 2010-02-23 14:41:18

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NHibernate: How to fetch an object without its child collections?

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