1. Carmen David, Senior BA Business Analysis Carmen David, Senior BA Business Analysis Foundation in Business Analysis Session 7 MODELLING REQUIREMENTS

2. Carmen David, Senior BA Business Analysis Function modelling –Use Case Diagrams Data modelling –Entity-Relationship Modelling –Class Diagrams Modelling Requirements Techniques?

3. Carmen David, Senior BA Business Analysis A use case diagram describes something the system is required to do for the business user A use case diagram is developed by adding all of the other functions the business users require the system to provide It shows the IT system from the user perspective Use Case Diagrams

4. Carmen David, Senior BA Business Analysis Use case diagram

5. Carmen David, Senior BA Business Analysis The system boundary is indicated by drawing a large box around all of the use cases but with the actors outside the box. It illustrates the scope of the system. Each use case is shown as an oval and represents a function that the system will perform in response to a trigger from the actor. We use the ‘verb–noun’ convention to name use cases, for example ‘Set up project’ or ‘Book room’. Actors are whoever or whatever expects a service from the system. They are usually user roles but may also be external systems or time. Actors are usually shown as matchstick figures, but if the actor is another system it can be shown by a rectangle with an > stereotype before the name of the system. Associations indicate which actors will need to interact with which use cases. Lines are drawn linking actors with the appropriate use cases. Use case diagram - Elements

6. Carmen David, Senior BA Business Analysis The > and > concepts allow use cases to be connected to each other. This is the only way in which use cases are linked, as these diagrams are not intended to show the flow – or sequence – of the processing. > and > constructs

7. Carmen David, Senior BA Business Analysis > indicates that the initial use case always want to also carry out the processing within the included use case (US 1 -> US2 (mandatory for US2)) > indicates that this is an optional link; the secondary use case is only required in certain situations (US1 <- US2 (not mandatory for US1)) > and > constructs

8. Carmen David, Senior BA Business Analysis Use case diagram

9. Carmen David, Senior BA Business Analysis Data modeling is concerned with identifying and understanding: the data items (attributes) that the organization (or system) needs to keep; the grouping of the attributes (into entities); the relationships between entities. Entity-Relationship Modeling

10. Carmen David, Senior BA Business Analysis Characteristics Entity Attributes Relationships Entity-Relationship Modeling

11. Carmen David, Senior BA Business Analysis An entity is something that the enterprise recognizes in the area under investigation and wishes to collect and store data about. An entity might be: physical, e.g. an order, a customer or a supplier; conceptual, e.g. a booking or an appointment; active, e.g. a meeting or a course. Entity

12. Carmen David, Senior BA Business Analysis Entities contain and are described by attributes Attributes may also be called data items. An attribute’s physical equivalent is a field. Attributes

13. Carmen David, Senior BA Business Analysis A relationship is a relevant business connection between two entities. A relationship is represented on a data model by a line linking the associated entities. Relationships may be: one-to-many (1:m); one-to-one (1:1); many-to-many (m:m). Relationships

14. Carmen David, Senior BA Business Analysis Relationships

15. Carmen David, Senior BA Business Analysis Relationships

16. Carmen David, Senior BA Business Analysis Exclusive Relationships

17. Carmen David, Senior BA Business Analysis A class diagram shows graphically the classes in a system and their associations with each other. –Objects –Classes –Associations Class Diagrams

18. Carmen David, Senior BA Business Analysis An object is something about which we wish to hold data, because that data is needed within the system we are analyzing –Account number: NX112G; –Name: Mr H. Hillman; –Credit limit: £8000; –Amount payable: £3500. Class Diagrams - Objects

19. Carmen David, Senior BA Business Analysis Classes provide the generic definition of the data items or attributes, and objects that are the instances of a particular class. In the UML, classes are represented by rectangular boxes with three sections The name of the class is shown in the top part and is a noun. The first letter is capitalised. Examples are ‘Account’, ‘Payment’ and ‘Transaction’. If the name is more than one word long, then the words are joined and each is capitalised in the class name Class Diagrams - Classes

20. Carmen David, Senior BA Business Analysis Attributes are the individual items of data about the class – are stored in the middle section. The first letter of the attribute name is not capitalised. Examples are ‘name’, ‘dateLastPayment’ and ‘creditLimit’. Operations are stored in the bottom part of the class and are invoked by messages being sent to the class by other classes. Class Diagrams - Classes

21. Carmen David, Senior BA Business Analysis Class

22. Carmen David, Senior BA Business Analysis The connections between classes are called ‘associations Types –An association with one-to-many multiplicity –An association with one-to-zero-to-one multiplicity –An association with one-to-one-to-many multiplicity –An association with one-to-one-to-20 multiplicity –An association with many-to-many multiplicity Class Diagrams - Associations

23. Carmen David, Senior BA Business Analysis Inherit and Generalization

24. Carmen David, Senior BA Business Analysis Thanks you! References: Business Analysis 2 nd edition by Debra Paul (Editor), Donald Yeates (Editor), James Cadle