Como usar savepoints no procedimento oracle

BEGIN

  Savepoint do_update_1;

  Update 1;

  insert 1;

  Update 2;

  Update 3; --Suppose exception occurs

EXCEPTION
  WHEN some_exception THEN Rollback To do_update_1;
END;

create table tttt(
  id int,
  val int
)
/

declare 
  x int := 0;
begin
  insert into tttt values( 1,1);
  insert into tttt values( 2,2);
  Savepoint do_update_1;

  insert into tttt values( 3,3);
  update tttt set val = 0 where id = 2;
  update tttt set val = 10 / val where id = 2;

exception
  when zero_divide then rollback to do_update_1;
end;
/