Breaking changes with NHibernate 4 upgrade

c# nhibernate hbm nhibernate-3 nhibernate-4
dove picture dove · Aug 22, 2014 · Viewed 8.3k times · Source

I can see what's new and fixed in NHibernate 4.0

I would like to know if anyone has had issue with hbm mappings upgrading from NHibernate 3 to 4?

I fear that more focus is going on fluent mapping these days. I can test for the more obvious breaking changes but wanted to know if there were any subtle issues that anyone has come across in a production environment that may not be so obvious at first.

It looks like a major upgrade and you'd expect there to be the risk of regressions.

Answer

ps2goat picture ps2goat · Nov 7, 2014

FYI, I found a new error that is thrown. We use Mapping By Code, and we used to have an entity that had multiple Bag mappings with the Fetch type set to Join with NHibernate v 3.3.x. This is no longer allowed in version 4.0.x.

We received an error message of Cannot simultaneously fetch multiple bags., which makes sense with what is necessary behind the scenes but it should technically be considered a breaking change. NHibernate was not nice enough to tell us which mapping was causing the issue.

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