1.查看表空间名称、大小、使用大小、剩余大小和使用率

单位换算：
1G=1024MB
1M=1024KB
1K=1024Bytes
1M=11048576Bytes
1G=1024*11048576Bytes=11313741824Bytes

SELECT a.tablespace_name "表空间名称", 
total / (1024 * 1024) "表空间大小(M)", 
free / (1024 * 1024) "表空间剩余大小(M)", 
(total - free) / (1024 * 1024 ) "表空间使用大小(M)", 
total / (1024 * 1024 * 1024) "表空间大小(G)", 
free / (1024 * 1024 * 1024) "表空间剩余大小(G)", 
(total - free) / (1024 * 1024 * 1024) "表空间使用大小(G)", 
round((total - free) / total, 4) * 100 "使用率 %" 
FROM (SELECT tablespace_name, SUM(bytes) free 
FROM dba_free_space 
GROUP BY tablespace_name) a, 
(SELECT tablespace_name, SUM(bytes) total 
FROM dba_data_files 
GROUP BY tablespace_name) b 
WHERE a.tablespace_name = b.tablespace_name

2.更改表空间大小(例如改为10G)

ALTER DATABASE DATAFILE '/表空间路径/表空间文件名称.dbf' RESIZE 10240M；

3.查看表空间是否自动增长

SELECT FILE_NAME,TABLESPACE_NAME,AUTOEXTENSIBLE FROM dba_data_files;

4.设置表空间自动增长

//打开自动增长
ALTER DATABASE DATAFILE '/表空间路径/表空间文件名称.dbf' AUTOEXTEND ON;
//每次自动增长200M
ALTER DATABASE DATAFILE '/表空间路径/表空间文件名称.dbf' AUTOEXTEND ON NEXT 200M ;
//每次自动增长200M，表空间最大不超过1G
ALTER DATABASE DATAFILE '/表空间路径/表空间文件名称.dbf' AUTOEXTEND ON NEXT 200M MAXSIZE 1024M;

5.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;

6.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;

7.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; 

8.查看控制文件

SELECT NAME FROM v$controlfile;

9.查看日志文件

SELECT MEMBER FROM v$logfile;

10.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; 

11.查看数据库库对象

SELECT owner, object_type, status, COUNT(*) count# 
FROM all_objects 
GROUP BY owner, object_type, status; 

12.查看数据库的版本

SELECT version 
FROM product_component_version 
WHERE substr(product, 1, 6) = 'Oracle'; 

13.查看数据库的创建日期和归档方式

SELECT created, log_mode, log_mode FROM v$database; 

原文链接：https://blog.csdn.net/ak57193856/article/details/79194011