Nine kinds of UML diagrams
Class Diagram
1. A class diagram describes the static structure of the classes in the system. Not only defines the classes in the system, but also represents the relationship between classes such as association, dependency, aggregation, etc., but also includes the internal structure of the class (class attributes and operations)
2. The class diagram is organized around the class, and other elements in the class diagram either belong to a class or are associated with a class
object graph
Referring to the class diagram, the difference is that the object diagram shows multiple instances of the class instead of the actual class
use case diagram
A use case diagram describes the system functions from the user's point of view, and is a model diagram of the system functions that users can observe. A use case is a functional unit in the system.
Flowchart
1. The sequence diagram shows the dynamic cooperative relationship between objects. It emphasizes the order in which messages are sent between objects and shows the interaction between objects.
2. One use of sequence diagrams is to represent the sequence of actions in a use case. When executing a use case behavior, each message in the sequence diagram corresponds to a class action
or the departure event that caused the state transition
Collaboration diagram
Collaboration diagrams describe the collaborative relationship between objects. Collaboration diagrams are similar to sequence diagrams and show dynamic cooperative relationships between objects. In addition to showing the exchange of information, collaboration diagrams also show objects and the relationships between them.
One use of a collaboration diagram is to represent the implementation of a class's operations
State diagram
A state diagram is a model diagram of all the journeys a class object may go through. A state diagram consists of the individual states of an object and the transitions that connect those states
Activity diagram:
1. An activity diagram is a variant of a state diagram that describes the activities involved in the workflow of executing an algorithm
2. An activity diagram describes a set of sequential or concurrent activities
component diagram
The component diagram models the components of the system—the components are the software units that construct the application—and also includes the dependencies between the components, so that the possible effects of modifications to the system components on the system can be estimated through these dependencies.
Deployment diagram
The deployment diagram is used to arrange the running of the component instances located on the nodes;