merge into test using dual on (Id = v_Id)
   when not matched then insert (Id, name, address) 
   values (v_Id, v_name, v_address)
   when matched then update set 

  name = v_name,  address = v_address;

create or replace TRIGGER test_trg before update on test for EACH ROW 

begin

If Updating Then

insert into test_log 
(name, address
)
values
(:new.name,

:new.address

);

if updating and :new.name <> :old_name 
then
   insert into test_log 
     (name, address)
      values
     (:new.name, :new.address);
end if;