Trigger Log Tabela

create or replace trigger GAT_AUMENTO_SALARIO
before update of salary
on employees
for each row
DECLARE
V_USERNAME varchar2(60);
begin
--seleciona o usuario logado do banco
select user into v_username from dual;
 insert into log_salario_employees values (:old.employee_id,:new.salary,:old.salary,SYSDATE,v_username);
 end;