declare
res char(1):='i';
create or replace procedure prod
(aid in number,aName in varchar2,astock in number)
as
begin
case res
when 'i'then insert into product values(aid,aName,astock);
when 'u' then update product set aid='34' where astock=20;
when 'd' then delete from product where astock=20;
end case;
end;