Nineth Chapter Trigger

Nineth Chapter Trigger


Section I: Introduction of triggers


A trigger (TRIGGER) is an action triggered by an event. These events include INSERT statements, UPDATE statements, and DELETE statements.
When the database system executes these events, the trigger is activated to perform the appropriate action.


Section II: Creating and Using triggers

2.1 Create a trigger that has only one execution statement

CREATE TRIGGER trigger name before | After Trigger event
On table name for each ROW execution statement


2.2 Creating a trigger with multiple execution statements

CREATE TRIGGER trigger name before | After Trigger event
On table name for each ROW
BEGIN
Execute statement List
END


Section III: viewing triggers

3.1 Show TRIGGERS statement view trigger information
3.2 Viewing trigger information in the Triggers table


Section Fourth: deleting triggers

DROP TRIGGER trigger name;

Nineth Chapter Trigger