IT Systems Analysis and Design

1. IT Systems Analysis and Design SSADM – Design Btec National - IT SYSTEMS ANALYSIS AND DESIGN

2. Aims • Gain further knowledge into the six stages of the development process (discuss the 3rd stage – Design) • Discuss input, output and process specifications • Gain an insight into ,pseudo code flowcharts and decision tables Btec National - IT SYSTEMS ANALYSIS AND DESIGN

3. SSADM • Design • This stage focuses on designing solutions that meet the requirements that were discovered in the analysis stage. • There are a number of keys parts to design, which are: • Input and output specifications • Process descriptors (this is the processes that transform the input into the required output) Btec National - IT SYSTEMS ANALYSIS AND DESIGN

4. SSADM • Design – input specification • This is the method/s used by the user to capture data. Examples include: • Bar-code readers • Magnetic strips • User entry (using keyboard and mouse) • Can you think of any more? • When data is enter manually validation and verification techniques should be used. • Remember GIGO Btec National - IT SYSTEMS ANALYSIS AND DESIGN

5. SSADM • Design Layouts – input specification • Can be designed using prototypes screens. These prototypes will not focus on the functionality just appearance. • The end-user will evaluate the prototypes and make requests. These requests will get implemented and the end-user will be asked for their opinion. • What would expect to see on a screen? Btec National - IT SYSTEMS ANALYSIS AND DESIGN

6. SSADM • Design Layouts – output specification • These would consist of screen outputs, reports or files. • What types of outputs can you think of? Btec National - IT SYSTEMS ANALYSIS AND DESIGN

7. SSADM • Design – Process descriptors • Processes would have been identified in the investigation stage. • It is important to define each process clearly to ensure that there is no unnecessary code implemented and the process does what was required. Btec National - IT SYSTEMS ANALYSIS AND DESIGN

8. SSADM • Design – Process descriptors • The following methods are used to create process specification: • Pseudo code • Flow charts • Decision tables Btec National - IT SYSTEMS ANALYSIS AND DESIGN

9. SSADM • Design - Pseudo code • Structured English - describes the process in English (as appose to programming code). • Example “Add fault to fault database” Open fault database Check if fault already exists, if it doesn’t Create new fault record Assign fault with unique fault number Request the user to input fault details Store fault details if fault already exists Display message to let the user know that the fault has already been logged Close fault database • You try and write some pseudo code to add a customer record to a database Btec National - IT SYSTEMS ANALYSIS AND DESIGN

10. SSADM • Design – Flow charts • These are diagrams used to show how processes link in a systematic (logical) way. • It graphically represents decisions, processes and where the overall processes starts and ends. Btec National - IT SYSTEMS ANALYSIS AND DESIGN

11. SSADM • Design – Flow charts • Ovals or circles are used to represent where the main process starts and ends • Decisions are represented as a diamond • Rectangles are for processes (Active verbs i.e. send, calculate) Btec National - IT SYSTEMS ANALYSIS AND DESIGN

12. Flowchart example We will attempt to model the pseudo code from the earlier example as a flowchart using Visio. Once you have helped your tutor complete the earlier example you need to attempt and create one yourself using the add customer example from earlier. Btec National - IT SYSTEMS ANALYSIS AND DESIGN

13. SSADM • Decisions tables • Useful when there are a lot of different options to choose from and you want to identify what happens in each circumstance. • Used when a flow chart would be too complicated to draw. Btec National - IT SYSTEMS ANALYSIS AND DESIGN

14. Decisions tables Btec National - IT SYSTEMS ANALYSIS AND DESIGN

15. Conclusion • Gained further knowledge into the six stages of the development process (discuss the 3rd stage – Design) • Discussed input, output and process specifications • Gained an insight into ,pseudo code flowcharts and decision tables Btec National - IT SYSTEMS ANALYSIS AND DESIGN