set linesize 120
col segment_name format a30
col segment_type format a16
col file_name format a45
col owner format a20
select file_name, segment_name, segment_type, owner  from dba_extents s, 
(select max(block_id) maxblock, file_id from dba_extents group by file_id) b, dba_data_files f where
s.block_id = b.maxblock and s.file_id = b.file_id and f.file_id = s.file_id
order by file_name
/