Yeah what you’re saying is right. In here I only took a 3-tiered architecture because it is easy for a beginner to get hold of. What I’ve said as the Application layer is a combination of domain logic and application logic both. But as you said of we want our application to be more structured, we should separate the application logic from the domain logic and put them into a separate layer.

Since this article is not intended to explain about layered architectures in deep, I thought of leaving it at only 3 tiers.

But what you are saying is 100% correct. Thanks for the valuable information.