In this chapter we have looked at a case study of a user privilege system. During the course of this exercise we have touched on requirements, design patterns, multi-tier architecture, and the design process.
A multi-tier approach has many advantages over other design patterns, the most important of which is modularity. In our case study, changing the layout of the forms would not alter the design of the database abstraction layer as it is wholly independent. Using this approach in our case study has shown how simple and useful it can be.
The modularity of the user privilege system also allows it to be extended in many ways. Firstly, it could be applied to itself. Only certain people can set privileges for others, so they should be given a relevant privilege before they can access the system. Other extensions are also possible.