Chapter 1 – Use Case Diagram

1.What is the Use Case Diagram?
The use case diagram is the diagram to visualize behavior/action that user/stakeholder may interact within the system

2.Element of the Diagram
2.1 Actor
-Visualized as a human shape
-Actors are users that perform actions to the system such as: Customer, Buyer, Seller, etc.
2.2 Use Case
-Visualize as a circle
-Each use case is an action/function/method that actor will perform to the system. For example: book ticket, buy ticket
2.3 System Boundary
-Visualize as a large rectangle line to hold all the use cases inside
-We need to name the system on the top middle of the system boundary

-There are relationships between use cases and actors as:
3.1 Association
-This is the compulsory relationship between actor—use case
3.2 uses / includes
-This relationship is used between a use case to a use case
-This mean one use case many uses/includes another use case
-Visualize as A use case ——–> includes a use case
3.2 extends
-This relation can be used for use case to use case OR actor to actor
-This mean as use case extends from a use case
-Visualize as Search a book < ——– extends Book a book
-An actor can extend from an other actor

4. Step to draw a Use Case Diagram
-List all the actors
-List all the use cases
-Draw system boundary and name the system
-Relationship between use case to use case
-Relationship between actor to actor
-Relationship between actor to use cases

App A: Note
-Use Verb + Noun/Noun Phrase for use case. For example: Book a ticket
-If we need to put words on the relation, follow the Verb + Noun/Noun Phrase rule

App B: Sample

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