System sequence diagram of Software Engineering

1. describes the events that external participants send to the system.

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

 

A use case has a system sequence diagram. The arrows in the system sequence diagram are drawn according to the main flow described in the use case;

The system sequence diagram is in chronological order from top to bottom. The sequence is in the order of main flow in the case description;

For example, the main flow of the logon case:

1. Enter the user name and password.

2. system verification.

3. Return to the logon page.

Therefore, there must be three messages in the system sequence diagram;

The system sequence diagram encapsulates the entire system, so the entire system is an object.

 

The system sequence diagram refers to the main flow without unexpected events.

The message name should start with a verb.

 

Indicates a loop statement;

SSD Template

The system sequence diagram shows the system-related input and output events, and treats the system as a black box, which describes the events and their sequence generated by external participants interacting with the system in a specific scenario. (1) makenewxxx () (2) doxxx () (3) endxxx ()