Foreword
Contacting the first few episodes of the video UML use case diagrams have a certain understanding of UML, then the use case diagram, what is it? Use Case Diagram What role do? What do I need to use time and attention to it?
A composition of the embodiment of FIG.
example
These observations are performed on a set of actions comprising variable sequences of actions, including the description of the system, and generates a transmission value of a particular participant. (We can understand the use cases are participants want the system to do)
Participants
Does not refer to people, it means using the system or interact with the system in the role outside of the system. (Example: Bob is a student systems administrator, then he is the administrator of this role can be as involved in the management)
relationship
Describes the relationship between actors and use cases
Association (→)
It is a containment relationship, i.e. a known class attributes and methods of another class.
Dependence (---->)
It is a use-dependent relationship, and changes in the parent class may affect the subclass, the need for coordination between the two, to use as little as possible.
Generalization (- ▷)
One of the inheriting relationship, subclass inherits the parent class, the arrow always points to the parent class.
System boundary
It represents a part of the correction system in a convenient boundary modeling system, a system outside the outer boundary
By action of the embodiment of FIG.
Use case diagram is a model diagram of a system function to external users can be observed, the system is the blueprint. (Meaning pave the way for software designers who use case drawing shows the functional block diagram)
Note that using local cases
1. It should be clearly defined system boundary
2. Example preventing excessive
3. It should be performed from the perspective of a person named in Example
4. The use case describes the normality of
5 to avoid inconsistent performer names
6. To avoid the relationship between the actors and the use cases too complicated
7. Note that with the embodiment is appropriate size
8 to avoid confusion with the described
examples
