The Four Types of Relationship in Use Case Diagram

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In UML, relationships are connections between model elements. Use cases are also connected to each other in different kinds of relationships. The relationship between two use cases basically models the dependencies between two use cases. By reusing existing use cases using different types of relationships, the overall effort required to develop the system is reduced.

Use case diagrams show use cases, actors, and the relationships between them. For example, the relationship between an actor and a use case illustrates that the actor can use certain functionality of the business system.

Association Relationships

An association is a relationship between two classifiers, such as an actor and use cases, that describes the cause of the relationship and the rules that govern it. An association is a relationship between an actor and a business use case. It indicates that an actor can use the functionality of the business system.

Use Case Diagram Example

Generalization Relationships

A generalization relation is a relationship in which one model element (child) is based on another model element (parent). Generalization relations are used in class diagrams, component diagrams, deployment diagrams, and use case diagrams to indicate that the child element accepts all the attributes, operations, and relationships defined in the parent element.

Use Case Diagram Generalization Example

Include Relationships

In UML modeling, a Include relationship is a relationship in which one use case (base use case) contains the functionality of another use case (inclusion use case). A containment relationship supports the reuse of functionality in the use case model.

Use Case Diagram Include Example

Extending relationships

In UML modeling, you can use an extend relationship to specify that one use case (extension) extends the behavior of another use case (base). This type of relationship reveals details about the system or application that are usually hidden in the use case.

Use Case Diagram Extend Example

More Use Case Examples

Broadcasting System Use Case Diagram

Use Case Diagram template: Broadcasting System Use Case Diagram (Created by Visual Paradigm Online's Use Case Diagram maker)

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ATM Use Case Diagram Example

Use Case Diagram template: ATM Use Case Diagram Example (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram: Multiple Projects with System Boundaries

Use Case Diagram template: Use Case Diagram: Multiple Projects with System Boundaries (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram: Online Examination System

Use Case Diagram template: Use Case Diagram: Online Examination System (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram Example: Passenger Service

Use Case Diagram template: Use Case Diagram Example: Passenger Service (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram Example: Software Development

Use Case Diagram template: Use Case Diagram Example: Software Development (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram Example: Carpark System

Use Case Diagram template: Use Case Diagram Example: Carpark System (Created by Visual Paradigm Online's Use Case Diagram maker)

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UML Use Case Diagram: Order Process System

Use Case Diagram template: UML Use Case Diagram: Order Process System (Created by Visual Paradigm Online's Use Case Diagram maker)

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Include and Extend Use Case Diagram

Use Case Diagram template: Include and Extend Use Case Diagram (Created by Visual Paradigm Online's Use Case Diagram maker)

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Use Case Diagram Example: Website (Extend and Include Use Case)

Use Case Diagram template: Use Case Diagram Example: Website (Extend and Include Use Case) (Created by Visual Paradigm Online's Use Case Diagram maker)