In the past I have primarily built all my web applications using an N-tier architecture, implementing the BLL and DAL layers. Recently, I have started doing some RoR development as well as looking into ASP.NET MVC.
I understand the differences between the different architectures(as referenced by some other SO posts), but I can’t really think of any reasons why I wouldn’t choose an MVC model going forward for a new project.
Is there any reasons/times in your experience when an MVC architecture would not be suitable, or any reasons why you would choose a BLL/DAL architecture instead?
One of the factors could be the statefulness of your web application. If it’s a basic web application that gets everything from the server with a few JavaScript hooks such as client side validations, then the Rails type MVC is really great. I am not familiar with MVC on ASP.NET, but I’ve heard it’s similar to that in Rails.
If the web application is really stateful, then a better approach would be to have a dual MVC layer – one on the client side, and the other for the server. The MVC on the server will mostly concern itself with authentication, authorization, churning out data in standard formats, etc. The client side MVC will concern itself with things such as DOM events, user actions, how they affect the application state, and how/when should data be requested/sent to the server.
MVC is just a way to organize code, just as BLL or DAL would do. MVC in Rails basically hides DAL altogether by using a set of conventions. Usually business logic resides in the models itself. However, if your application demands more complex BLL where object interactions can be intricate, then there’s no reason why that BLL can’t peacefully co-exist with the M in MVC.