Check datafiles and tablespace information in Oracle
Check information about datafiles
SQL> select * from dba_data_files;
SQL> select * from v$datafile;
Check information about tablespace
SQL> select * from dba_tablespaces
SQL> select * from v$tablespace;
check size of datafiles
select file_name,bytes/1024/1024/1024 from v$datafile;
Check the tablespace size
SELECT df.tablespace_name "Tablespace",
totalusedspace "Used MB",
(df.totalspace - tu.totalusedspace) "Free MB",
df.totalspace "Total MB",
ROUND(100 * ( (df.totalspace - tu.totalusedspace)/ df.totalspace)) "% Free"
FROM
(SELECT tablespace_name,
ROUND(SUM(bytes) / 1048576) TotalSpace
FROM dba_data_files
GROUP BY tablespace_name
) df,
(SELECT ROUND(SUM(bytes)/(1024*1024)) totalusedspace,
tablespace_name
FROM dba_segments
GROUP BY tablespace_name
) tu
WHERE df.tablespace_name = tu.tablespace_name;