What exactly consists of 'Business Logic' in an application?

Question

I have heard umpteen times that we \'should not mix business logic with other code\' or statements like that. I think every single code I write (processing steps I mean) con

Answer 1

If it contains anything about things like form, button, etc.. it's not a business logic, it's presentation layer. If it contains persistence to file or database, it's DAL. Anything in between is business logic. In reality, anything non-UI sometimes gets called "business logic," but it should be something that concerns the problem domain, not house keeping.