CREATE TABLE historico (
estacion NUMBER(4),
linea NUMBER(4),
numorden NUMBER(4),
fecha VARCHAR2(40),
usuario VARCHAR2(10),
operacion VARCHAR2(20))

CREATE OR REPLACE TRIGGER ejer3tren
after INSERT OR DELETE ON linea_estacion
FOR each ROW
BEGIN
    IF inserting THEN
        INSERT INTO historico VALUES (:NEW.estacion, :NEW.linea, :NEW.numero_orden, TO_CHAR(SYSDATE, 'dd/mm/yyyy - HH24:Mi:SS'), USER, 'Insertado');
    ELSIF deleting THEN
        INSERT INTO historico VALUES (:old.estacion, :old.linea, :old.numero_orden, TO_CHAR(SYSDATE, 'dd/mm/yyyy - HH24:Mi:SS'), USER,'Borrado');
    END IF;

END;
/