We have pretty large classes which we persist using NHibernate.
I raised issue NH-655 on the NHibernate Jira--for which there was a workaround--and the issue was closed with the remark that

Could someone please supply a guideline as to what is "too big"? How many properties, relationships to other objects and sets of child objects would be regarded as too many? Or is it inappropriate to have a rule of thumb for this?

Thanks

Ian Douglas

by "Too Big", what are we talking about?

how many lines is your mapping file?

We have a mapping file per entity and there are about 220 entities. The largest entity has 13 child sets, and about 190 properties and many-to-one references to other objects. The objects in the child sets also have--in some cases--numerous properties and many-to-one references, as do the objects referred to via many-to-ones.

It would be quite an exercise to go though all the mapping files to produce a total, because this is a large application.

If you can supply a failing test case for the bug, I will certainly look into fixing it.

Right, that sounds huge and hard to measure.

But this strikes me as a smell: .

I don't to suggest that your object model is bad (b/c I don't know your domain/problem) but I can see why this might be difficult to work with in NHibernate.

I mean, does this object map to a single table? A single table with 190 columns?

I'd be a little hesitant in providing a full test case (which I'd have to reconstruct anyway), because potentially I'd be letting the intellectual property of a very large commercial bank out of the door.

The three largest tables in our database schema--which are mapped using NHibernate--have 225, 116 and 110 columns respectively. This is not unheard of in applications such as the one I'm working on, and the DBMS (Oracle) can cope with this scenario without difficulty.

But I don't have any interest in the intellectual property of a very large commercial bank. All I care about is to have a class structurally similar to that of yours, including the implementation of GetHashCode and other things that may be relevant to the problem, and a simple test that shows the bug.

I understand that it requires some effort on your side to provide this test case but you are the only person so far who experienced the problem.

Unfortunately I don't have time to recreate a complex set of classes of the type required. I'm in the middle of a project.

The unit tests in the NHibernate.Test assembly don't seem to include any class with a large number of properties (although I haven't checked all the test fixtures). How much testing for this type of usage--numerous properties, numerous many-to-one relationships, numerous sets--has been done on NHibernate?

No such testing has been done on NHibernate.