All of the samples we covered in this chapter were of the 1-tier n-layer style. We learned how to create a 1-tier 2 layer architecture using logical code separation. Then we focused on the need for a 3-layered solution and examined ER-diagrams, domain models and UML, all of which are important tools that aid in the understanding of commercial projects required to build a 3-layered structure.

Then we focused on a 3-layered application structure for OMS, and looked at how both custom code and object data source controls can be used in this architecture.

In the coming chapters, we will discuss the need to physically separate this 3-layered code into "tiers", and see how we need a different model to achieve this goal and create scalable n-tier applications.