1.查看表空间使用情况：

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;

2、查看数据库库对象

select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status;

3、查看数据库的版本

Select version FROM Product_component_versionWhere SUBSTR(PRODUCT,1,6)='Oracle';

4、查看数据库创建日期和归档方式

Select Created, Log_Mode, Log_Mode From V$Database;

5、查询数据库中索引占用表空间的大小

select a.segment_name,a.tablespace_name,b.table_name,a.bytes/1024/1024 mbytes,a.blocks

from user_segments a, user_indexes b

where a.segment_name = b.index_name

and a.segment_type = 'INDEX' --索引

and a.tablespace_name='APPINDEX' --表空间

and b.table_name like '%PREP%' --索引所在表

order by table_name,a.bytes/1024/1024 desc