I have two simple classes with such mappings:



and code for work with objects:



Method session.Flush() causes exception:



I can save objects only by session.Save(), but it is not convenient. Who was confronted with such problem help me, please

P.S. Cascade deletion works properly

Serega

As far as i know, cascading transitive persistence only applies to save (update), delete and reattaching. Flush is something different. In your case, I would recommend using session.SaveOrUpdate(). I'm not sure why session.Save() would be more inconvienent than session.Flush() but I don't know your system.

-devon

I can use session.Save() or session.SaveOrUpdate() of cource, but I want use just cascades, it is most convenient approach for my tasks . There is an example in chm-reference in NHibernate distribution, chapter 6.3 "Cascading lifecycle". It is almost the same as my code example, but authors say it works.

Okay, I get it, I misread your code and didn't see that you were loading the parent object from the db. In your case I think the problem is that cascading works by comparing the "unsaved-value" attribute to determine whether the object needs to be "cascaded."

Also, I think you are going to have problems because you are assigning the id of the child class. I don't know how NH would be able to determine if this was a transient object since you are assigning the id directly.

You can try adding the "unsaved-value" attribute to your <id> mapping-- most people use "0" or "-1"-- but I don't know what you would do for the <id> property of the ChildClass mapping.

-devon

Edit: I just read through section 6.4 of the reference-chm and the answer is in there. Apparently you will have to give NH a hint and there are three options-- two of them involve calls to session.Save() or session.Update()...

actually if you read the docs (if they are accurate):

3.1.4.7. Assigned Identifiers
If you want the application to assign identifiers (as opposed to having NHibernate generate them), you may use the assigned generator. This special generator will use the identifier value already assigned to the object's identifier property. Be very careful when using this feature to not assign keys with business meaning (almost always a terrible design decision).

Due to its inherent nature, entities that use this generator cannot be saved via the ISession's SaveOrUpdate() method. Instead you have to explicitly specify to NHibernate if the object should be saved or updated by calling either the Save() or Update() method of the ISession.