查看数据库信息

查看数据库的SQL
1、查看表空间的名称及大小

set linesize 140;
set pages 200;
column tablespace_name format a30;

select tablespace_name,min_extents,max_extents,pct_increase,status from dba_tablespaces;

select tablespace_name,initial_extent,next_extent,contents,logging,extent_management,allocation_type
from dba_tablespaces
order by tablespace_name;

2、查看表空间物理文件的名称及大小

column db_block_size new_value blksz noprint
select value db_block_size from v$parameter where name='db_block_size';
column tablespace_name format a16;
column file_name format a60;
set linesize 160;
select file_name,round(bytes/(1024*1024),0) total_space,autoextensible,increment_by*&blksz/(1024*1024) as incement,maxbytes/(1024*1024) as maxsize from dba_data_files order by tablespace_name;

3、查看回滚段名称及大小

COLUMN roll_name FORMAT a13 HEADING 'Rollback Name'
COLUMN tablespace FORMAT a11 HEADING 'Tablspace'
COLUMN in_extents FORMAT a20 HEADING 'Init/Next Extents'
COLUMN m_extents FORMAT a10 HEADING 'Min/Max Extents'
COLUMN status FORMAT a8 HEADING 'Status'
COLUMN wraps FORMAT 999 HEADING 'Wraps'
COLUMN shrinks FORMAT 999 HEADING 'Shrinks'
COLUMN opt FORMAT 999,999,999 HEADING 'Opt. Size'
COLUMN bytes FORMAT 999,999,999 HEADING 'Bytes'
COLUMN extents FORMAT 999 HEADING 'Extents'

SELECT
a.owner || '.' || a.segment_name roll_name
, a.tablespace_name tablespace
, TO_CHAR(a.initial_extent) || ' / ' ||
TO_CHAR(a.next_extent) in_extents
, TO_CHAR(a.min_extents) || ' / ' ||
TO_CHAR(a.max_extents) m_extents
, a.status status
, b.bytes bytes
, b.extents extents
, d.shrinks shrinks
, d.wraps wraps
, d.optsize opt
FROM
dba_rollback_segs a
, dba_segments b
, v$rollname c
, v$rollstat d
WHERE
a.segment_name = b.segment_name
AND a.segment_name = c.name (+)
AND c.usn = d.usn (+)
ORDER BY a.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 * from( select sum(bytes)/(1024*1024) as "free_space(M)",tablespace_name
from dba_free_space
group by tablespace_name) order by "free_space(M)";

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 * from v$version;

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;

10、查看临时数据库文件

select STATUS, ENABLED, NAME from v$tempfile;

12 查看 SGA 内存大小
SQL> SHOW SGA;

Total System Global Area 524288000 bytes
Fixed Size 1220336 bytes
Variable Size 155189520 bytes
Database Buffers 360710144 bytes
Redo Buffers 7168000 bytes
SQL> SELECT * fROM V$SGA;

NAME VALUE
-------------------- ----------
Fixed Size 1220336
Variable Size 155189520
Database Buffers 360710144
Redo Buffers 7168000