IN THIS CHAPTER

The previous chapter introduced some of the elements of the infrastructure necessary to support our design, dealing primarily with the back end and the database technology. That discussion stressed the need to separate business rules from the physical access technologies, such as SQL construction and eventual execution of the query. The same message will be emphasized in this chapter, but the focus will be broader and serve as a means to assess our architecture one more time and it will be a bit more specific, through the creation of a sequence diagram.

A good way to show this back-to-front process is to start with the user interface, such as an HTML form, and follow its path through all the layers. This chapter will also begin to explore the means of our presentation in the form of servlets and JavaServer Pages.