How to create Triggers in Oracle

List all triggers

SELECT * FROM USER_TRIGGERS

Create Trigger

CREATE TRIGGER TRI_PRETECHEMPLOYEE
BEFORE INSERT OR UPDATE ON PRETECHEMPLOYEE
FOR EACH ROW
BEGIN
DBMS_OUTPUT.PUT_LINE('Trigger started');
END;

Note: PRETECHEMPLOYEE table needs to be created.

Drop a trigger

DROP TRIGGER TRI_PRETECHEMPLOYEE

Please see this link to know more about Triggers Oracle Triggers