UML Learning (1)

I have always wanted to take a good look at UML. Last summer I systematically read a book and experienced it myself in the project. I feel that UML is quite useful as an auxiliary tool for system analysis and design, however, I was still using Visio to draw a UML diagram ,:(. The text below will record some of your understanding and insights in the UML learning process. If you are biased, you can still correct it.

1. What is UML? What is it used?

UML, unified modeling language, and unified modeling language. As the name suggests, it is used for modeling. So why do we need modeling? As we all know, transactions and objects are inextricably linked in the real world. In actual project development, many roles, functions, and business processes are often involved, if we present these in text, it will be very lengthy and the natural language is prone to ambiguity. Therefore, in actual operations, we often choose to use models to represent complex system functions and business processes, add appropriate text descriptions when necessary. The model is the abstraction of real transactions and the simplification of real systems. UML can meet the requirements of modeling.

2. Why use UML?

There are many modeling methods. Why should we use UML? For example, I can now create a model based on my own design habits in Visio: In this model, I use an ellipse to represent classes, a fine arrow to represent inheritance, and a straight line to represent implementation. The question is, can someone else understand my graph? Maybe others always use rectangles to represent classes? This problem won't occur when you use UML, because UML has become a standard modeling language for software and system development. Since it is a standard, of course it will be used, if the standard representation is used, it means that you do not have to re-learn modeling technology every time you change jobs, so that you are not afraid to adapt to new jobs after job hopping, ^_^.

3. Some Basic Concepts

Modeling Language: any language that contains a notation and a description of its meaning;

Notation: A method used to represent a model. It is an element of a modeling language;

Meta-Model (semantics): Describes the meaning of each element in the representation method, such as what the rectangle represents and what the arrow represents;

Profile: a custom description of a specific field (such as banking;

4. UML Model View

We can break down the UML Model diagramCapture specific aspects of the systemPerspective or view, that is, the UML

The charts are classified as follows (4 + 1 view model ):

Logical view: it is used to model the components of the system and how components are combined, such as class diagrams, object graphs, and interaction diagrams;

Process view: Describes the processes in the system, such as the activity diagram;

Development View: describes how system components form modules and components, such as package charts and component diagrams;

Object view: describes how the system design described in the first three views is implemented in real-world entities, such as deployment diagrams;

Use Case view: describes the functional requirements of the system. All other views are guided by the use case view, for example, the use case diagram;