Generally, IS A and HAS A can be used to determine which relationship is used. The generalization relationship and extension relationship represents the IS A relationship between the use examples, including relationships, represents the HAS A relationship between the use cases. Compared with the extension and generalization relationship, the concept of extension points, that is, an extension can only be expanded on the extension of the basic use case.
In the extended relationship, the basic use case is a use case that can be used independently. When a basic use case is executed, it can be executed or the extended portion may not be performed.
In the inclusive relationship, the basic use case may, or may not be a Well formed. When performing basic use cases, it will be performed to include a portion of the INCLUSIE Case.
If you need to repeat two or more use cases, you can consider using the included relationship to implement a reference to another use case.
When dealing with normal behavior, it is only an occasional description, it can be considered only using the general relationship.
When describing a normal behavior is described, it is desirable to use more control mode, and the expansion point can be set in the basic use case, and the extended relationship is used.
The extended relationship is a more difficult concept in UML. If the extended relationship is regarded as an extensive relationship with more rule restrictions, it can help understand. In fact, before the UML Specification 1.1 version, the extension relationship is the version of the generalization relationship. After the 1.3 version, the extended relationship is changed to the version of the dependency.
Here, you summarize the differences and links between the UML relationship, association, generalization, dependency.
The relationship is a specific semantic connection between the model elements. Relationships can be divided into several association, generalization, dependence, etc., and there is another relationship is implementation.
Association is the relationship between two or more classificions, which describes the connection between instances of the class. The type of class herein is a modeling element that includes a class (CLASS), a participant, component, data type (data type), interface, node (Node) ), Signal, Subsystem, Use case, etc., where the class is the most common class.
The generalization relationship is expressed as the relationship between two types. Among these two elements, a relatively universal, a relatively special. Examples of relatively special types can appear anywhere in the example of relatively universal class, that is, relatively special types of elements are consistent with relatively universal types in structure and behavior, but relatively special The class contains more information.
Dependencies are a relationship between two elements and elements, and the dependent element is called a target element, depending on the elements, called the source element. When the target element changes, the source element must do a corresponding change. It contains relationships and extension relationships that belong to dependencies.
