CREATE TABLE log_trigger (num NUMBER(10), texte VARCHAR2(100));
CREATE SEQUENCE seq_cpt2 START WITH 1 increment BY 1 ;
CREATE OR REPLACE TRIGGER avantInsertion
before INSERT ON categories
BEGIN
    --insert or update or delete on categories
  INSERT  INTO Log_trigger VALUES (seq_cpt2.NEXTVAL, 'test trigger before');
END avantInsertion;

CREATE OR REPLACE TRIGGER apresInsertion
after INSERT ON categories
BEGIN
  INSERT  INTO Log_trigger VALUES (seq_cpt2.NEXTVAL, 'test trigger after');
END apresInsertion;


--insertion dans la table categories
SELECT * FROM categories;
SELECT * FROM log_trigger;

INSERT INTO categories
VALUES (60,'valeur de la sequence :' || seq_cpt2.NEXTVAL);
ROLLBACK;