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use case diagram (UML use case diagram)

Contributor(s): Stan Gibilisco

A use case diagram is a graphic depiction of the interactions among the elements of a system. 

A use case is a methodology used in system analysis to identify, clarify, and organize system requirements. In this context, the term "system" refers to something being developed or operated, such as a mail-order product sales and service Web site. Use case diagrams are employed in UML (Unified Modeling Language), a standard notation for the modeling of real-world objects and systems.

System objectives can include planning overall requirements, validating a hardware design, testing and debugging a software product under development, creating an online help reference, or performing a consumer-service-oriented task. For example, use cases in a product sales environment would include item ordering, catalog updating, payment processing, and customer relations. A use case diagram contains four components.

  • The boundary, which defines the system of interest in relation to the world around it.
  • The actors, usually individuals involved with the system defined according to their roles.
  • The use cases, which are the specific roles played by the actors within and around the system.
  • The relationships between and among the actors and the use cases.

A use case diagram looks something like a flowchart. Intuitive symbols represent the system elements. Here's a simple example:

Use case diagram restaurant model

This was last updated in January 2015

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what is user case
I'm sure you meant "Use case". Everything was mentioned above.

Use cases help to define functional requirements. Functional requirement define WHAT a system must do, but NOT HOW it must be done.

Use cases describe the system functions from the perspective of system users and in a manner and terminology they understand.

Use cases are the beginning of a USE CASE DRIVEN approach to systems analysis and design. They have impact on the analysis, programming, testing and documentation. Use cases are very important.
good topic
Had a good exposure towards the topic.thanks for the post
UML is nothing necessarily new.  I learned about them when i was in college, as part of ways to visualize requirements and fleshing out designs.  The reality is, I haven't seen much UML in use in the last five years.  They can still be useful for helping to visualize scenarios in an application, and I believe that many of the feature stories you'll find in agile teams, that the process of making the UML use case diagram is still there behind the scenes, we just don't always draw them out.
Hi, I have a question. When do we use stereotype 'private' and 'subtype' in visio for stereotyping uses arrows. Can someone help please


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