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

I dont like the BLL+DAL names of the layers, they are more confusing than clarifying.
Call it DataServices and DataPersistence. This will make it easier.

Services manipulate, persistence tier CRUDs (Create, Read, Update, Delete)