create or replace trigger tfa_user_biu
    before insert or update
    on tfa_user
    for each row
begin
    if :new.userid is null then
        :new.userid := to_number(sys_guid(), 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX');
    end if;
    if inserting then
        :new.created := sysdate;
        :new.created_by := nvl(sys_context('APEX$SESSION','APP_USER'),user);
    end if;
    :new.updated := sysdate;
    :new.updated_by := nvl(sys_context('APEX$SESSION','APP_USER'),user);
end tfa_user_biu;