-The first type is the Use Case Diagram
Describes the system functionality from the user's point of view, and indicates the operators of each function.
-The second category is the Static
diagram
which includes class diagrams, object diagrams, and package diagrams. Class diagrams describe the static structure of classes in a system. It not only defines the classes in the system and represents the connections between classes such as associations, dependencies, aggregations, etc., but also includes the internal structure of the classes (their attributes and operations). A class diagram describes a static relationship that is valid throughout the life cycle of a system. Object diagrams are instances of class diagrams and use almost the same identifiers as class diagrams. They differ in that object diagrams show multiple object instances of a class rather than the actual class. An object diagram is an instance of a class diagram. Since objects have a life cycle, an object diagram can only exist at a certain time in the system. A package consists of packages or classes and represents the relationships between packages. Package diagrams are used to describe the hierarchical structure of a system.
-The third category is the Behavior
diagram
describes the dynamic model of the system and the interactions between the constituent objects. A state diagram describes all possible states of the objects of a class and the conditions under which the state is transferred when an event occurs. In general, statecharts are complementary to class diagrams. In practice, it is not necessary to draw state diagrams for all classes, but only for those that have multiple states and whose behavior is affected and changed by the external environment. Activity diagrams, on the other hand, describe the activities that need to be performed to satisfy the requirements of a use case and the constraints between them, and are useful for identifying parallel activities.
-The fourth category is the Interactive
diagram
describing the interaction between objects. Among them, the sequence diagram shows the dynamic cooperation between objects, it emphasizes the order of sending messages between objects, and at the same time shows the interaction between objects; cooperation diagram describes the collaborative relationship between objects, cooperation diagram is similar to the sequence diagram, shows the dynamic cooperation between objects. In addition to showing the exchange of information, the cooperation diagram also shows the objects and the relationship between them. Sequence diagrams are used if time and order are emphasized, while cooperation diagrams are chosen if hierarchical relationships are emphasized. These two types of diagrams are collectively called interaction diagrams.
-The fifth category is the implementation diagram (
Implementation
diagram
). The
Implementation
diagram describes the physical structure of code components and the dependencies between them. A component may be a resource code component, a binary component, or an executable component. It contains information about logical classes or implementation classes. Component diagrams help to analyze and understand the degree of interaction between components.
A configuration diagram defines the physical architecture of hardware and software in a system. It can show the actual computers and devices (represented by nodes) and the connections between them, as well as the types of connections and dependencies between components. Inside the node, executable components and objects are placed to show the correspondence between the node and the executable software unit.
From an application point of view, when designing a system using object-oriented techniques, the first step is to describe the requirements; the second step is to build a static model of the system based on the requirements in order to construct the structure of the system; and the third step is to describe the behavior of the system. In the first step and the second step in the establishment of the model are static, including use case diagrams, class diagrams (including packages), object diagrams, component diagrams and configuration diagrams and other five graphics, is the standard modeling language UML static modeling mechanism. Which the third step in the establishment of the model either can be executed, or to represent the execution of the timing of the state or interaction. It consists of four graphs such as state diagrams, activity diagrams, sequence diagrams and cooperation diagrams, which is the dynamic modeling mechanism of the Standard Modeling Language UML. Therefore, the main content of the standard modeling language UML can also be summarized into two categories: static modeling mechanism and dynamic modeling mechanism.