1. Architecture

2. Stuff to memorise…
"A method tells an object to perform an action. A property allows us to read or change the settings of the object."

3. Architecture Planning and designing a successful system
Use tried and tested techniques
Easy to maintain
Robust and long lasting

4. The DVD Swap Shop Written in VB.NET Suffers from much poor design
Available for download from the module web site / blackboard
We shall look at a quick demo of what the program does

5. Maintenance DVD Swap Shop built on Access
Not the best choice for an internet application
Change to another database e.g. SQL Server
DVD.MDB becomes DVD.MDF

6. The Problem
Web page 1
Database Name
Web page 2
Web page 3
Web page 4
Data Connection Class
Database
100 page site with ten references to the database per page = 1000 changes to the code!

7. Scalability How many of you have FaceBook or Twitter on your phone?
How would we modify the DVD swap shop so there is a phone app that does the same?
Re-design the pages
However what do we do about the functionality?

8. Compare the Following Pages

9. Other Issues to Think About
Dealing with International Markets
Dealing with Different Computer Platforms

10. Dealing with International Markets

11. Amazon Search

12. Dealing with Different Computer Platforms
Mobile Apps - Apple/Android/Windows
PCs e.g. iOS / Windows/ Android
Linux machines
Servers running Apache / IIS
What is the technology that makes it possible to support such a range of platforms?

13. Simple Three Layered Architecture
Presentation
(Interface)
Data Layer
Database
Middle Tier
Business Logic
(Objects/Classes)

14. Benefits : Change Database Technology without Changing the Interface
The interface has no knowledge of the structure of the database
Middle tier handles communication of data
Database technology may be changed with no impact on interface
All functionality in the middle tier
This means we may bolt on many different interfaces

15. Benefits : Attach Multiple Presentation Layers
(Interface)
Web browser
Data Layer
Database
Middle Tier
Business Logic
(Objects/Classes)
Mobile phone app

16. Benefits : Code re-use and maintenance
All important code is stored in the middle layer
Any changes made here benefit all parts of the system using it
Code only created once so easier to find an maintain

17. Overview of Finished Address Book

18. The Presentation Layer

19. The Middle Layer

20. The Data Layer