System sequence diagram of software engineering

1. Describe the events that the external participants sent to the system.

2. Describe the communication between the system and the system.

A use case has a system sequence diagram, the arrows drawn in the system sequence diagram are drawn according to the use case description of main flow;

The system sequence diagram represents the order of time from top to bottom, and the order of the main flow according to the use case description;

For example, the main flow of a login use case:

1. User input user name and password

2. System verification.

3. Return to the login page.

Therefore, there must be 3 messages in the system sequence diagram as well;

System sequence diagram because the entire system is encapsulated, the entire system is an object.

The system sequence diagram refers to the flow of main flow, regardless of unexpected events.

The message name is best to start with a verb.

Represents a loop statement;

SSD Templates

The system sequence diagram illustrates the system-related input and output events, and treats the system as a black box, explaining the events and their order of interaction between the external participants and the system in a given scenario;

(1) makenewxxx (

2) doxxx ()

(3) EndXxx ()