Tutorial video : UML Use-Case diagrams

Tutorial video  : UML Use-Case diagrams 

Use Case Diagrams

nUse Case diagrams show the various activities the users can perform on the system.

nSystem is something that performs a function.

nThey model the dynamic aspects of the system.

nProvides a user’s perspective of the system.

nA set of ACTORS : roles users can play in interacting with the system.

nAn actor is used to represent something that users our system.

nA set of USE CASES: each describes a possible kind of interaction between an actor and the system.

nUses cases are actions that a user takes on a system

nA number of RELATIONSHIPS between these entities (Actors and Use Cases).

nRelationships are simply illustrated with a line connecting actors to use cases.

Use Case Diagrams - Actors

nAn actor  is  a user of the system playing a particular role.

nActor is shown with a stick figure.

Use Case Diagrams – Use Cases

nUse case is a particular activity a user can do on the system.

nIs represented by an ellipse.

nFollowing are two use cases for a library system.

Tutorial video  : UML Use-Case diagrams