YOOT

Hammett has a post where he, among others, advises:

I don’t encourage people to use AR with the AR base class. Use the
ARMediator and use the repository pattern or a dao pattern to increase
isolation and testability.

Yes ! It seems not many people knew it (I did, I'm a Reflector addict lol) but you can use ActiveRecord without base classes for your entities (ActiveRecordBase), just use the [ActiveRecord] attribute.

That way, you get:

• Attribute-based mapping declaration (instead of manual edition of NHibernate mapping files, which can be cumbersome).
• Well-tested plumbing code like session & transaction scopes.
• Easy querying through ActiveRecordMediator static methods, instead of direct use of NHibernate ISession.

Now, if you want the best ORM experience in a DDD-context:

• Use the Repository pattern, to get an additional layer of abstraction between your application code & your particular ORM.
• Use Linq queries in your repositories, for rich ORM-independent querying capabilities (your ORM has to support Linq of course).

I've been refactoring & cleaning up some code lately, I will soon drop the first draft of Yoot.DomainDriven, a non-intrusive framework for pragmatic Domain-Driven Design with nice abstraction of Units of work & Linq-friendly repositories, and implementations for mainstream ORM tools.