That's a long story, and I'm no academic. I'll try to formulate an answer, and (I hope) others will correct me where I go wrong :)
midix wrote:
where they use some base classes and interfaces to implement common functionality in the domain model. But still the model entities contain some persistence awareness because of that inheritance.
You can define a three-tier architecture where you keep all your persistence-related stuff in the DAL. The BL, although it inherits from the base-class, can be separate from the DAL - even physically on another machine if needs be. Yes, there will still be a relation between those two. The things are loosely coupled, instead of intermixed throughout the entire codebase. Loose coupling has the advantage that you can replace it quickly, simply by writing new derived classes (or new base-classes). You cannot avoid the coupling completely; there's some part in your application that needs to know where to persist, and how.
midix wrote:
And if we forget for a moment about that ServiceLyer but stick to the classical MVC - then where is the right place for CRUD operations when using ORM? Is it Controller or Model?
I'd say neither. Your controller could populate the model with information from the BL-classes, which could be derived from the DAL-classes. Even if you don't follow the three-tier architecture; the controller isn't forced to do SQL - but it sure is convenient if you can LINQ there :)
I are troll :)
