uml--use case diagram

Objective

UML is used to describe the entire design process of the system, and for this process produced a UML9 diagram: Use case diagram, Class diagram, object graph, collaboration diagram, sequence diagram, activity diagram, state diagram, Component diagram and deployment diagram. Mind Mapping

use case diagram First, Introduction

According to the above map, we first introduce the use case diagram, from the user's point of view to describe the requirements, the desired implementation of the system functions and performers. A use case diagram consists of a use case, a role, and a relational three parts. second, the process

In the design process to pay attention to:

1. Clear function, no specific implementation method required

2. Define the properties of the use case diagram (event flow, general and expected path description: Alternative flow, other factors generated, execution of other paths; preconditions, prerequisites for event flow execution; Post condition, System state at end of use case)

3. Define the granularity and scope of use cases (decomposition of the classification, and the impact on code implementation and system patching)

4. Clear definition of the system boundary, the performer angle naming use case three, example

This figure includes a total of 3 roles for general users, operators, and administrators. Contains the following relationships:

1. Association: Divided into two-way and one-way, generally the relationship between roles and use cases

2. Generalization: The common behavior of certain roles is extracted to represent common behavior, for example: inheritance relationship ...

3. Include: Include, the behavior of one use case contains the behavior of another use case

4. Extension: Extend, new behavior added by this use case, incremental extension summary

Theory requires hands-on practice, in writing this article query a lot of UML use case diagram. May still be defective, please leave some comments and suggestions for this article below.