One: Class diagrams (Behavior classes and entity classes)---> class diagrams are used to show the classes in the system and their relationship to each other---> Conceptual layer class Diagram---> Description layer class DiagramSecond: Concept layer class Diagram---> Concept view: Class Diagrams At this level describe the conceptual understanding of problem areas in the real world. ---> at the conceptual level, class diagrams focus on conceptual understanding of problem areas rather than implementations, so class names are often the names of actual things in the problem domain. is at the conceptual stage. ---> such as: Online shopping mainly by the goods, orders, payment cards, such as the composition of several categories.Three: Description Layer class Diagram---> Description layer diagram is a bridge between the real world and the final realization. ---> At this stage, the class is usually very sketchy, although it expresses the computer viewpoint, but in the description it uses the approximate present world language, in order to guarantee from the real world to the code realization excessively. ---> such as: The attribute of the class is described in words, and the behavior functionFour: Implement Layer class Diagram---> Implementation layer views that the class is the description of the implementation code, and the classes in the class diagram map directly to the executable code. ---> At this level, classes must explicitly adopt that implementation language, what design patterns, what communication standards, and what specifications to follow. ---> Implementation Layer Class diagram is probably the most common, many people do not have the concept layer and the class diagram of the description layer when modeling, and directly jump to implement layer class diagram. The reason is not that they confirm that the problem areas are well understood, and that the design experience is rich, but usually there are three levels of views that do not know about the class diagram.Five: Package diagram---> Package diagrams are generally used to show high-level views---> In all views of UML, package diagrams is perhaps the freest and least constrained. In addition to the specific version, the package can be used almost at any stage. ---> Presents a topological chart of the system's partition area from a visual angle.
< 14 >uml Core view static view and so on diagram and package diagram
