UML Use Case "extend" and "include" relationships
For example, imagine "Withdraw Cash" is a use case of an Automated Teller Machine The key to Include and extend use case relationships is to realize that . This use case diagram relationships tutorial will cover all you need to know about relationships in use cases. Learn about include, extend. The correct way to indicate a "include" or "extend" relationship is with a Example. But I'm not sure, once I'm also learning I hope it helps.
Modelling the whole system will lead to a lot of work that nobody will ever look at and which will soon again be out of date.
So I'm currently creating an UML Use case diagram to describe the basic features of my application I'm planning to develop and it always happens again to me that I come to the point where I have to search the web about the details regarding the "extend" and "include" relationships. Just out of the head it seems to be clear: But still there are these doubts This behavior is modeled with a base use case called CheckOrderStatus that has an inclusion use case called LogIn.
The LogIn use case is a separate inclusion use case because it contains behaviors that several other use cases in the system use. An include relationship points from the CheckOrderStatus use case to the LogIn use case to indicate that the CheckOrderStatus use case always includes the behaviors in the LogIn use case.
The "extend" relationship is explained as follows: You are developing an e-commerce system in which you have a base use case called Place Online Order that has an extending use case called Specify Shipping Instructions. An extend relationship points from the Specify Shipping Instructions use case to the Place Online Order use case to indicate that the behaviors in the Specify Shipping Instructions use case are optional and only occur in certain circumstances. So the key point in the extends relationship is "optional"!
An include dependency, formerly known as a uses relationship in UML v1. The best way to think of an include dependency is that it is the invocation of a use case by another one. The blue test in Figure 2 presents an example of how you would indicate where the use case is included in the logic of the including use case.
Similar to calling a function or invoking an operation within source code, isn't it? You use include dependencies whenever one use case needs the behavior of another.
UML Use Case "extend" and "include" relationships
Introducing a new use case that encapsulates similar logic that occurs in several use cases is quite common. For example, you may discover several use cases need the behavior to search for and then update information about students, indicating the potential need for an "Update Student Record" use case included by the other use cases.
Why should you bother maintaining an "Includes" and an "Extends" list in your use cases? The answer is simple: Yes, it would be nice if everyone has access to the use-case diagram because it also contains this information, but the reality is that sometimes you use different tools to document each part of your model. For example, your diagrams could be drawn using a drawing package and your use cases documented in a word processor. Some of your project stakeholders may have access to the word processor you are using, but not the drawing package.
The main disadvantage of this approach is you need to maintain these two lists in parallel with the diagram, the danger being they may become unsynchronized.
Reuse in Use-Case Models: >, >, and Inheritance
Inheritance Between Use Cases Use cases can inherit from other use cases, offering a third opportunity to indicate potential reuse. Figure 1 depicts an example of this, showing that "Enroll Family Member in University" inherits from the "Enroll In University" use case.
Inheritance between use cases is not as common as either the use of extend or include dependencies, but it is still possible. The inheriting use case would completely replace one or more of the courses of action of the inherited use case. In this case, the basic course of action is completely rewritten to reflect that new business rules are applied when the family member of a professor is enrolling at the university.
UML Use Case Include
Family members are allowed to enroll in the school, regardless of the marks they earned in high school, they don't have to pay any enrollment fees, and they are given top priority for enrollment in the university. Inheritance between use cases should be applied whenever a single condition, in this case, the student is a family member of a professor, would result in the definition of several alternate courses.
Without the option to define an inheriting use case, you need to introduce an alternate course to rework the check of the student's high-school marks, the charging of enrollment feeds, and for prioritization of who is allowed to enroll in the given semester. The inheriting use case is much simpler than the use case from which it inherits.
It should have a name, description, and identifier, and it should also indicate from which use case it inherits in the "Inherits From" section.
This includes any section that is replaced, particularly the pre-conditions and post-conditions as well as any courses of action. If something is not replaced, then leave that section blank, assuming it is inherited from the parent use case you might want to put text, such as "see parent use case," in the section.
Inheritance Between Actors The fourth opportunity for indicating potential reuse within use-case models occurs between actors: An example of this is shown in Figure 1the "International Student" actor inherits from "Student.
The standard UML notation for inheritance, the open-headed arrow, is used and the advice presented about the appropriate use of inheritance still applies: The DAD framework is a people-first, learning-oriented hybrid agile approach to IT solution delivery.Include relationship in use case diagram(In hindi ) by Hightech
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