Systems Analysis and Design in a Changing World, Fifth Edition

1. Systems Analysis and Design in a Changing World, Fifth Edition

2. Systems Analysis and Design in a Changing World, 5th Edition User Goals, Events, and Use Cases • Use Case -- An activity the system performs in response to a user request • Techniques for identifying use cases • User goal technique - Each goal at the elementary business process (EBP) level is a use case • CRUD analysis technique (create, read, update, delete)‏ • Event decomposition technique

3. Systems Analysis and Design in a Changing World, 5th Edition Use Case Descriptions • Use case description – a description of the processing steps for a use case • Actor – a person or thing that uses the system. Actors have contact with the system • Scenario or Instance – a particular set of internal steps that represent a unique path of the use case • Three types of descriptions: • Brief, Intermediate, Fully developed

4. Systems Analysis and Design in a Changing World, 5th Edition Brief Description Figure 5-13

5. Systems Analysis and Design in a Changing World, 5th Edition Intermediate Description Figure 5-14

6. Systems Analysis and Design in a Changing World, 5th Edition Fully Developed Description Figure 5-16

7. Systems Analysis and Design in a Changing World, 5th Edition Identifying Use Cases Based on User Goals Figure 5-1

8. Systems Analysis and Design in a Changing World, 5th Edition Use Case Based on CRUD Technique Figure 5-2

9. Systems Analysis and Design in a Changing World, 5th Edition Event Decomposition Technique • Event – an occurrence at a specific time and place and which needs to be remembered • Business events trigger elementary business processes (EBPs)‏ • Identify business events to decompose system into activities/use cases

10. Systems Analysis and Design in a Changing World, 5th Edition Types of Events • External • Outside system • Initiated by external agent or actor • Temporal • Occur as result of reaching a point in time • Based on system deadlines • State • Something inside system triggers processing need

11. Systems Analysis and Design in a Changing World, 5th Edition External Event Checklist Figure 5-4

12. Systems Analysis and Design in a Changing World, 5th Edition Temporal Event Checklist Figure 5-5

13. Systems Analysis and Design in a Changing World, 5th Edition Events Deferred Until the Design Phase Figure 5-8

14. Systems Analysis and Design in a Changing World, 5th Edition Information about Each Event in an Event Table Figure 5-11

15. Systems Analysis and Design in a Changing World, 5th Edition “Things” in the Problem Domain • Define system requirements by understanding system information that needs to be stored • Store information about things in the problem domain that people deal with when they do their work

16. Systems Analysis and Design in a Changing World, 5th Edition Types of Things Figure 5-18

17. Systems Analysis and Design in a Changing World, 5th Edition Procedure for Developing an Initial List of Things • Step 1: Using the event table and information about each use case, identify all nouns • Step 2: Using other information from existing systems, current procedures, and current reports or forms, add items or categories of information needed • Step 3: Refine list and record assumptions or issues to explore • Questions to include it, exclude it, or research it

18. Systems Analysis and Design in a Changing World, 5th Edition Relationships Between and Characteristics of Things Figure 5-20

19. Systems Analysis and Design in a Changing World, 5th Edition Data Entities • Things system needs to store data about in traditional IS approach • Modeled with entity-relationship diagram (ERD)‏ • Requirements model used to create the database design model for relational database

20. Systems Analysis and Design in a Changing World, 5th Edition The Entity-Relationship Diagram (ERD)‏ Figure 5-23

21. Systems Analysis and Design in a Changing World, 5th Edition Expanded ERD with Attributes Shown Figure 5-25

22. Systems Analysis and Design in a Changing World, 5th Edition ERD with Many-to-Many Relationship Figure 5-27

23. Systems Analysis and Design in a Changing World, 5th Edition Many-to-Many Relationship Converted to Associative Entity to Store Grade Attribute Figure 5-28

24. Systems Analysis and Design in a Changing World, 5th Edition The Domain Model Class Diagram • Unified Modeling Language (UML) diagram • Domain model class diagram • Models things in the users’ work domain • Used to define requirements for OO (very similar to entities in ERD)‏

25. Systems Analysis and Design in a Changing World, 5th Edition UML Class Symbol Figure 5-30

26. Systems Analysis and Design in a Changing World, 5th Edition Simple Domain Model Class Diagram Figure 5-31

27. Systems Analysis and Design in a Changing World, 5th Edition Multiplicity of Associations Figure 5-32

28. Systems Analysis and Design in a Changing World, 5th Edition University Course Enrollment Domain Model Class Diagram Figure 5-33

29. Systems Analysis and Design in a Changing World, 5th Edition Refined Model with Association Class and Grade Attribute Figure 5-34

30. Systems Analysis and Design in a Changing World, 5th Edition A Generalization/Specialization Class Hierarchy for Motor Vehicles Figure 5-35