New to NHIbernate and working thru making a decision on whether or not to use the attribute based approach available in 1.2 over and against the tradition separate hbm.xml files.

Any opinions either way on this???

Thanks - wg

I wrote a similar question but no takers ;-)
The overall best-practices opinion is that attributes are best. There are some dissenters but not many.

It means you have refactorable attribute-code (avoids constantly editing text files to change variable/column names), it's unintrusive in that even though you need the attribute dll, this is just metadata, you don't NHibernate assembly to compile the code that contains the attributes.

A small benefit might be that startup would be faster because there's no XML to parse (I've no idea how much of a difference this would make in practice).

And, you write less code/text because you can inherit properties that have attributes on them, if writing XML, you often have to repeat the XML fragment for each and every class.

And Ayende uses attributes. That's worth a few points... ;-) I think just because they're a 'lot easier'.

From some authorative point of view, the book 'Hibernate In Action' co-authored by a guy who wrote the original Hibernate, seriously recommends attributes over XML for new projects.

IMHO, the attributes are much easier to maintain.

I've been reading thru the NHibernate In Action book and I think you're right ... they do seem to lean towards using attributes.

Are there any code gen tools that actually generate partial classes with attribute based mappings?

How are you all proceeding with development using this approach?

thanks - wg

I looked at using attributes since I used them in Java and they were great, but the documentation seemed to be completely missing. Is there a place I should be looking other than the main reference? The only thing there seems to be 2 or 3 pages long and mostly useless. Are there good examples out there? Can you do everything you can do with mapping files with attributes?

From what I've read there are some things you can't do with Attributes. At a guess they're probably not worth doing... For examples, I download the NHibernate source code and have a look at the tests. They use all possible attribute mappings.