What is Use Case Diagram?
UML Use Case diagram example in Sparx Systems Enterprise Architect. A Test Case is a stereotyped Use Case element which enables you to give greater An Association implies that two model elements have a relationship, usually. Create Use Case Diagram for describing the behavior of the target system from an An association specifies a semantic relationship that can occur between. UML use cases share different kinds of relationships. A relationship between two use cases is basically a dependency between Essentially, the "Perform Pathological Tests" use case is a specialized version of the generic.
Someone interacts with use case system function.
Actor plays a role in the business Similar to the concept of user, but a user can play different roles For example: Actor has responsibility toward the system inputsand Actor have expectations from the system outputs. Do something Each Actor must be linked to a use case, while some use cases may not be linked to actors.
Communication Link The participation of an actor in a use case is shown by connecting a actor to a use case by a solid link. Actors may be connected to use cases by associations, indicating that the actor and the use case communicate with one another using messages. Boundary of system The system boundary is potentially the entire system as defined in the requirements document.
For large and complex systems, each modules may be the system boundary.
For example, for an ERP system for an organization, each of the modules such as personal, payroll, accounting, etc. The entire system can span all of these modules depicting the overall system boundary Structuring Use Case Diagram with Relationships Use cases share different kinds of relationships. Defining the relationship between two use cases is the decision of the software analysts of the use case diagram. A relationship between two use cases is basically modeling the dependency between the two use cases.
Reuse of an existing use case by using different types of relationships reduces the overall effort required in developing a system. Use case relationships are listed as the following: Use Case Relationship Visual Representation Extends Indicates that an "Invalid Password" use case may include subject to specified in the extension the behavior specified by base use case "Login Account". Depict with a directed arrow having a dotted line. The tip of arrowhead points to the base use case and the child use case is connected at the base of the arrow.
Use Case Diagram notations guide - Visual Paradigm
A use case includes the functionality described in another use case as a part of its business process flow.
A uses relationship from base use case to child use case indicates that an instance of the base use case will include the behavior as specified in the child use case. An include relationship is depicted with a directed arrow having a dotted line.
The tip of arrowhead points to the child use case and the parent use case connected at base of the arrow.UML Use Case Diagram Tutorial
Generalization A generalization relationship is a parent-child relationship between use cases. The child use case in the generalization relationship has the underlying business process meaning, but is an enhancement of the parent use case. UC34 Perform Security Check. Applicable to Step 17] 8.
The system determines that the applicant does not already exist within the system according to BR37 Potential Match Criteria for New Students. The system determines that the applicant is on the eligible applicants list.
Person is Not Eligible to Enroll] The system adds the applicant to its records. The applicant is now considered to be a student. The registrar helps the student to enroll in seminars via the use case UC 17 Enroll in Seminar.
The student pays the initial fee. The system prints a receipt. The registrar hands the student the receipt. The use case ends. Include Dependencies Between Use Cases A second way to indicate potential reuse within use-case models exists in the form of include dependencies. 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.
Creating Use Case Diagrams
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. 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? Figure elaborates on the Administer System use case in Figure using extend dependencies. It shows that a system administrator is offered two options starting up the system or shutting down the system at the extension point named Administration Functions, which is described as being available on the administration menu of the user interface.
Figure further shows the following: Extension points and extend dependencies The Startup System use case is available as an option at the Administration Functions extension point of the Administer System use case. The Startup System use case has two extension points named Before and After.
The Before extension point is described as occurring before the startup functionality is performed by the system, and the After extension point is described as occurring after the startup functionality is performed by the system. These extension points are used as follows: The Restore Data use case is available as an option at the Before extension point of the Startup System use case. Before starting up the system, the system administrator may restore data from the backup system to the project management system's database that was previously archived.
There are no options described for the After extension point of the Startup System use case. The Shutdown System use case is available as an option at the Administration Functions extension point of the Administer System use case. The Shutdown System use case has two extension points, named Before and After. The Before extension point is described as occurring before the shutdown functionality is performed by the system, and the After extension point is described as occurring after the shutdown functionality is performed by the system.
The Backup Data use case is available as an option at the After extension point of the Shutdown System use case. After shutting down the system, the system administrator may back up data from the project management system's database to the backup system for later retrieval. There are no options described for the Before extension point of the Shutdown System use case.
The extension points just described allow us to insert behavior into the Startup System and Shutdown System use cases before or after they perform startup or shutdown processing for the project management system. The extend dependencies reference these extension points to indicate where use cases may be inserted inside one another, and also to indicate the conditions that must be satisfied for such an insertion to occur.