1、查看表空间的名称及大小    select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size
    from dba_tablespaces t, dba_data_files d
    where t.tablespace_name = d.tablespace_name
    group by t.tablespace_name;2、查看表空间物理文件的名称及大小    select tablespace_name, file_id, file_name,
    round(bytes/(1024*1024),0) total_space
    from dba_data_files
    order by tablespace_name;3、查看回滚段名称及大小    select segment_name, tablespace_name, r.status,
    (initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent,
    max_extents, v.curext CurExtent
    From dba_rollback_segs r, v$rollstat v
    Where r.segment_id = v.usn(+)
    order by segment_name ;4、查看控制文件    select name from v$controlfile;5、查看日志文件    select member from v$logfile;6、查看表空间的使用情况    select sum(bytes)/(1024*1024) as free_space,tablespace_name
    from dba_free_space
    group by tablespace_name;    SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE,
    (B.BYTES*100)/A.BYTES "% USED",(C.BYTES*100)/A.BYTES "% FREE"
    FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE C
    WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;7、查看数据库库对象    select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status;8、查看数据库的版本    Select version FROM Product_component_version
    Where SUBSTR(PRODUCT,1,6)='Oracle';9、查看数据库的创建日期和归档方式    Select Created, Log_Mode, Log_Mode From V$Database;