text: create table foo(id varchar(15), parent_id varchar(10), rdate datetime);
  insert into foo values('UMN_000223', 'UMN_000222',null);
  insert into foo values('UMN_000224', 'UMN_000222',null);
  insert into foo values('UMN_000225', 'UMN_000222',null);
  insert into foo values('UMN_000221', 'UMN_000221',null); 
  
  UPDATE foo
  SET   rdate = '1999-12-12 12:12:12.123'
  WHERE  id IN (SELECT id
                     FROM   foo
                     START WITH parent_id = 'UMN_000222'  
                     CONNECT BY PRIOR id = parent_id);
  
  select * from foo order by 1;
  
  drop table foo;
  