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The full name of UM is unified modeling language, which is a unified modeling language. UML can help us with software requirements and software design,

1.1umlDefinition

UML is a common visual modeling language. It is a standardized language that uses graphical modeling (modeling) and a representation of object-oriented analysis and design. It is a document used to describe the software, visualize the processing, construct and establish the software system. UML is applicable to various software development methods, various stages of the software life cycle, various application fields, and various development tools. UML can describe the static structure and dynamic behavior of the system: the static structure defines the attributes and operations of important objects in the system, and the relationships between these objects; dynamic Behavior defines the time characteristics of the object and the mechanism by which the object communicates with each other to complete the target task. UML is not a programming language, but we can use a code generator to convert a UML model into multiple programming language code, or use a reverse Generator tool to convert the program source code to a UML model.

It includes two concepts: semantics and representation.

(1) semantics describes UML-based Precise meta-model definitions using natural languages. The meta-model provides simple, consistent, and general definitions for all UML elements in terms of syntax and semantics, enabling developers to achieve semantic consistency, eliminate the impact of the best expressions that vary from person to person. In addition, UML also supports the extension definition of the metadata model.

(2) The notation defines the notation of UML symbols, which provides a standard for System Modeling by developers or development tools using these graphical symbols and text syntax. These graphical symbols and texts express an application-level model, which determines that UML is a visual (graphical) modeling language.

UML diagrams can be divided into two types: structural diagrams and behavioral diagrams.

 

	UML diagram	Description
Structural Diagram (Structure digoal)	Class digraphs)	Must be used to analyze business concepts
	Object digraphs)	Rarely used
	Component Diagram)	Used to analyze IT infrastructure and software architecture requirements
	Deployment Diagram)
	Package digraphs)	Rarely used
Behavior chart Behavior digoal	Activity digraphs)	You must use at least one of the charts to analyze the business process. In most cases, you must use at least two of them.
	State Machine digraphs)
	Sequence digraphs)
	Communication Diagram)
	Use case diagram)	Must be used to express the vast majority of software analysis requirements
	Time Sequence)

 

The link types in UML are:

1. Dependency
2. . Join
3. . Generalization
4. .

 

2. UMLModeling steps

There are two modeling mechanisms in UML: Static Modeling Mechanism and dynamic modeling mechanism.

When we use object-oriented design and analysis methods in practical applications, we generally follow the following steps:

The first step is to understand the requirements. This step generally produces a use case diagram.

Step 2: establish the static model of the system as needed and construct the system structure;

This step generates: class diagram, object diagram, component diagram, and deployment diagram.

Step 3: describe the behavior of the system. The model created here can be executed, or the time sequence status or Interaction relationship during execution.

This step generates: status chart, activity chart, and Sequence Chart.

The models created in step 1 and Step 2 are both static models. We call them static modeling, and the third step is called activity modeling.

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Future content will be related to the following requirements:

[Requirements of a company's kaol System]
A company is a software company with approximately 100 employees. Most of its employees are software developers, including project managers, software designers, programmers, test engineers, and implementation engineers, in addition, it also includes administrative staff, financial staff, and the company has a set of management methods in software research and daily management. Prior to the absence of the kaol system, the management work related to kaol is as follows:
1: Each employee needs to take a card at work in the morning and a card at work in the afternoon,
2: If you need to go out to work during the period, you need to get a card when you leave the company, and you need to get another card when you return to the company.
3.
4: The Administration Department collects kaule information every day, including logging information, outgoing information, and leave information, and submits the summary information to the finance department every month.
5: the accounting department adjusts the employee's salary based on the summary information of kaol.

In addition, consider other incidents:
1: An employee wants to take annual leave. However, the Administration Department informs the employee that the annual leave for the current year has been completed, and the management of the annual leave has encountered problems, which may affect the employee's work enthusiasm.
2: An employee complained that the current month's salary had been deducted because the kaol information statistics were incorrect. As a result, the finance department pushed the responsibility to the Administration Department. The requirements of the accounting department of the Administration Department were unclear.
3.

Therefore, this system is used to improve the efficiency and accuracy of kaol's work, so as to avoid the impact of normal work due to kaol problems.

The above requirements come from [fireball UML war Demand Analysis.

 

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