(Note: The examples are simplified)I've seperated my solution into 3 projectsWebSiteBusiness LogicData Access LogicThe Website has access to BL and DALThe BL has access to nothingThe DAL has access to the BLOn the website I can do something likeBL.User user = DAL.GetUser(1)I also have this type of logic in the websiteuser = [new user information]If Not DAL.DoesEmailExists(user) Then    DAL.InsertNewUser(user)End IfWhat would be my option to remove this if/insert from the website?My ideal option would be to put this logic inside the BL.User but that's not possible. If the BL has access to the DAL it will make a circular reference.
3 Tier Application Architecture, logic and database
.net;architecture
This type of code actually belongs in the Business Layer, from where you control the behavior of your application, make decisions about inserting an object or displaying an alert to the user, etc.,// BLIf Not DAL.Exists(user) Then    DAL.InsertNewUser(user)Else    // Maybe warn the user about inserting a duplicate user object    WL.Alert(User already exists!) End IfYou BL should then have access to both the DAL and the WL, and your DAL should not have a dependency on the BL (it only knows how to retrieve data on demand). Do not confuse a Business Object (BO), which can also be a Data Transfer Object (DTO), with a BL: a BO is simply for transferring or passing data from layer to layer. 