Use C ase M odel and Use Case D iagrams. Juna Somare (2008-BCT-515) Pratima Lingden(2008-BCT-524) Sabanam Lakhey (2008-BCT-533). Use case model . A set of scenarios that describes an interaction between a user and a system
A use case diagram is “a diagram that shows the relationships among actors and use cases within a system.”
Use case diagrams are often used to:
Communicate the scope of a development project
Provide an overview of all or part of the usage requirements for a system or organization in the form of an essential model or a business model
Model your analysis of your usage requirements in the form of a system use case model
Use Case Diagrams have 4 major elements:
1. Actor: Represented by using stick person icon.
Figure: Online shopping
Figure: Implying timing considerations between use cases
3. Relationship : Lines connecting two modeling elements with an optional open-headed arrowhead on one end of the line
Figure: Enrolling students in a university
The system shall log credit payments to the accounts receivable system. The lack of context makes room for ambiguity.
Use cases break requirements down into short "stories" so that readers can more easily understand the system.
Not good at capturing non-functional requirements.
No guarantee of templates clarity.
difficult to avoid the temptation of describing user interface too early.
Low information content.