Use case diagrams
What is a Use Case Diagram?
A use case diagram is a dynamic or behavior diagram in UML. Use case diagrams model the functionality of a system using actors and use cases. Use cases are a mix of actions, services, & functions that the system needs to lớn perform. In this context, a "system" is something being developed or operated, such as a web site. The "actors" are people or entities operating under defined roles within the system.
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Why Make Use Case Diagrams?
Use case diagrams are valuable for visualizing the functional requirements of a system that will translate into design choices & development priorities.
They also help identify any internal or external factors that may influence the system & should be taken into consideration.
They provide a good high level analysis from outside the system. Use case diagrams specify how the system interacts with actors without worrying about the details of how that functionality is implemented.
Basic Use Case Diagram Symbols and Notations
SystemDraw your system"s boundaries using a rectangle that contains use cases. Place actors outside the system"s boundaries.
Use CaseDraw use cases using ovals. Label the ovals with verbs that represent the system"s functions.
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ActorsActors are the users of a system. When one system is the actor of another system, label the actor system with the actor stereotype.
RelationshipsIllustrate relationships between an actor và a use case with a simple line. For relationships among use cases, use arrows labeled either "uses" or "extends." A "uses" relationship indicates that one use case is needed by another in order khổng lồ perform a task. An "extends" relationship indicates alternative options under a certain use case.
Use Case Diagram Tool Tutorial
Start with one of loadingvn.com"s blank UML diagram templates or an included use case diagram example. You can quickly showroom shapes and users & connect them. To showroom text, just click and type.
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Tips for UML Use Case Diagrams
When thinking of use cases, think of the kết thúc goal of a user. They don"t want khổng lồ "login" or "sign up." That"s not a use case. The use case is more like "make a purchase."
Actors don"t have names. They"re not "Bob." They represent the role of someone interacting with the system.
Keep your names short & the kích thước of your use cases consistent for a professional look.
For a detailed implementation of a user"s goal use a sequence diagram.
Use Case Diagram Examples
The best way lớn understand use case diagrams is to lớn look at some examples of use case diagrams.
