-- Trigger Function()
-- --------------------------------------------------------------------------------------
-- FUNCTION: public.pedvendabi()

-- DROP FUNCTION IF EXISTS public.pedvendabi();

CREATE OR REPLACE FUNCTION public.pedvendabi()
    RETURNS trigger
    LANGUAGE 'plpgsql'
    COST 100
    VOLATILE NOT LEAKPROOF
AS $BODY$
declare
   mreg smallint;
begin
  select MAX(cppedvenda) INTO mreg from pedvendas;
  if ( mreg is null )
  then
     NEW.cppedvenda := 5;
  else
     NEW.cppedvenda := mreg + 5;
  end if;
  return new;
end;
$BODY$;

ALTER FUNCTION public.pedvendabi()
    OWNER TO postgres;
-- --------------------------------------------------------------------------------------
Gatilho na Tabela
-- --------------------------------------------------------------------------------------
-- Trigger: bipedvendas

-- DROP TRIGGER IF EXISTS bipedvendas ON public.pedvendas;

CREATE OR REPLACE TRIGGER bipedvendas
    BEFORE INSERT
    ON public.pedvendas
    FOR EACH ROW
    EXECUTE FUNCTION public.pedvendabi();