Use Case Diagram - Extend Notation

This section describes the Extend Notation used in a UML Use Case Diagram. An Extend Notation presents an extension relation between two use cases where one acts as the base use case and the other acts as an add-on use case.

An Extend Notation is a graphical notation used in a UML Use Case Diagram to represent an extension relation between two use cases where one acts as the base use case and the other acts as an add-on use case. The base use case is usually called the Extended Use Case. The add-on use case is usually called the Extending Use Case.

An Extend Notation is usually drawn as a dash line with a line arrow connecting both use cases. The arrow of an Extend Notation should point to the extended use case. An Extend Notation should also be labeled with the "<<extend>>" key word.

For example, the "On-Line Help" use case is an extension to the "Place Order" use case. This extension relation can be drawn as an Extend Notation in a UML use case diagram as shown below:
UML Notation Shape - Extend

Last update: 2014.

Table of Contents

 About This UML Tutorial Book

 Introduction of UML (Unified Model Language)

 UML Class Diagram and Notations

 UML Activity Diagram and Notations

 UML Sequence Diagram and Notations

 UML State Machine Diagram and Notations

UML Use Case Diagram and Notations

 What Is a Use Case Diagram?

 Use Case Diagram - Use Case Notation

 Use Case Diagram - Actor Notation

 Use Case Diagram - Association Notation

Use Case Diagram - Extend Notation

 Use Case Diagram - Include Notation

 MS Visio 2010 - UML Drawing Tool

 References

 PDF Printing Version