NHibernate or Fluent NHibernate? [closed]

Question

I would be interested in hearing op opinions from others regarding whether which they would choose (no 'neithers' please ;), and why.

What are the downsides to using fluent? (version dependancy maybe?) Pros, Cons, Experiences etc.

Answer 1

Fluent NHIbernate sits on top of NHibernate, so its not really a choice between the two. If youre going to use NHibernate, CHOOSE to use Fluent NH on top of it to save yourself vast amounts of effort.

Fluent NHibernate is awesome, I wouldn't use NHibernate without it. You can fluently map all your entities (giving you compile time checking, and automated testing support) instead of having to maintain cumbersome xml files and remember their syntax/DTD.

It can also automatically map your entities based on default and/or your own custom conventions.

Just use it!

Answer 2

I would definitely say go with fluent-nhibernate. Just be aware it may not necessarily be as smooth a ride as you would hope.

1. Regarding version dependency

   1. I have had a 'reverse' dependency issue when upgrading to a new version of FNH required me to upgrade to a new version of NH (2.0 to 2.1 I think). This was not a major issue for me.
   2. I just recently (this morning) dropped NH 2.1.1 into the FNH 1.0 RTM (this is distributed with 2.1.0) without any dramas (yet).

2. Edit: Since writing this post FNH has matured substantially to the point where I do not think this is a real issue anymore Mapping support - some mappings are not yet possible with fluent nhibernate. However, this is NOT a reason to avoid FNH as hybrid fluent-xml mappings allow you to fallback on traditional xml in the event of fluent being unable to map it (although this is only on per-class granularity). Examples of mappings:

   1. Cannot yet map fields - http://groups.google.com/group/fluent-nhibernate/browse_thread/thread/a7787927dafd23a/84ce2616946a18d7
   2. Cannot map some times of dictionary http://groups.google.com/group/fluent-nhibernate/browse_thread/thread/d38b6c72250cd2fb - actually from what I gather this functionality exists but is not in the mainline yet.

3. Compound complexity factor. From the sounds of it you will be learning both FNH and NH at the same time. For the majority of fairly simple applications this is fine - infact FNH is often so good that you need to know fairly little about the hbm.xml mappings. But if you want to go do something reasonably complex, it will rarely work the first time round and you are left wondering if it is a PEBKAC, fluent or NH issue. More often than I'd hoped I ended up writing the traditional xml mappings (of course, you are doing this anyway, but it would have been preferable not to expend more effort than necessary fiddling with fluent first).