CREATE or replace TRIGGER PersonCheckAge
AFTER INSERT OR UPDATE OF age ON Person
FOR EACH ROW
BEGIN
IF (:new.age < 0) THEN
RAISE_APPLICATION_ERROR(-20000, 'no negative age allowed');
END IF;
END;


insert into Person values (53);

create table persona (
idPersona numeric primary key,
edad      numeric,
constraint checkEdad check (edad >=0));

create sequence personaSeq

insert into persona values (personaSeq.nextval,10)

insert into persona values (11,10)

select * from persona

insert into persona values (10)

delete from persona