What is the difference between include and extend relationship?
“The include relationship is intended for reusing behaviour modeled by another use case, whereas the extend relationship is intended for adding parts to existing use cases as well as for modeling optional system services” (Overgaard and Palmkvist, Use Cases: Patterns and Blueprints.
How do you represent include and extend relationship in UML?
In UML notation the include relationship annotated with the <> keyword and a dashed arrow pointing towards the include use case. Include relationship may or may not appear on its own as a behavior sequence. Extend relationship is one where the extension use case adds itself to the base use case.
What is << include >> in use case?
<> relationships: Include relationship is used to include one use case within the behavior sequence of another use case. An include relationship between use cases means that the base case explicitly incorporates the behavior of another use case at a location specified in the base.
What does extend mean in UML?
Extend is a directed relationship that specifies how and when the behavior defined in usually supplementary (optional) extending use case can be inserted into the behavior defined in the extended use case. Extended use case is meaningful on its own, it is independent of the extending use case.
What is include relationship?
In UML modeling, an include relationship is a relationship in which one use case (the base use case) includes the functionality of another use case (the inclusion use case). The include relationship supports the reuse of functionality in a use-case model.
What is the difference between include and extend in UML?
Extend is used when a use case conditionally adds steps to another first class use case. Include is used to extract use case fragments that are duplicated in multiple use cases.
What is extend relationship?
An extend-relationship is a relationship from an extension use case to a base use case, specifying how the behavior defined for the extension use case can be inserted into the behavior defined for the base use case. It is implicitly inserted in the sense that the extension is not shown in the base use case.
What are the roles of include and extend relationship?
Extend is used when a use case conditionally adds steps to another first class use case. Include is used to extract use case fragments that are duplicated in multiple use cases. The included use case cannot stand alone and the original use case is not complete without the included one.
What is the difference between uses and extends?
Uses is an imprecise term for UML diagrams and typically should be avoided. Extends refers to some action or mini-use case that is optional (not necessarily just for error handling). If you have a use case for making a withdrawal from an ATM, you might extend that use case with a print balance use case.
What is an extension point?
In UML models, an extension point identifies the point in the base use case where the behavior of an extension use case can be inserted. The extension point is specified for a base use case and is referenced by an extend relationship between the base use case and the extension use case.
What is an extend relationship?
In UML modeling, you can use an extend relationship to specify that one use case (extension) extends the behavior of another use case (base). The extend relationship specifies that the incorporation of the extension use case is dependent on what happens when the base use case executes.
What is an include relationship in UML?