http://www.blogjava.net/xiaohewoai/archive/2010/02/01/311532.html
查看当前用户的缺省表空间
SQL>select username,default_tablespace from user_users;

查看当前用户的角色
SQL>select * from user_role_privs;

查看当前用户的系统权限和表级权限
SQL>select * from user_sys_privs;
SQL>select * from user_tab_privs;

查看用户下所有的表
SQL>select * from user_tables;

显示用户信息(所属表空间)
select default_tablespace,temporary_tablespace
from dba_users where username='GAME';

1、用户

查看当前用户的缺省表空间
SQL>select username,default_tablespace from user_users;

查看当前用户的角色
SQL>select * from user_role_privs;

查看当前用户的系统权限和表级权限
SQL>select * from user_sys_privs;
SQL>select * from user_tab_privs;

显示当前会话所具有的权限
SQL>select * from session_privs;

显示指定用户所具有的系统权限
SQL>select * from dba_sys_privs where grantee='GAME';

显示特权用户
select * from v$pwfile_users;

显示用户信息(所属表空间)
select default_tablespace,temporary_tablespace
from dba_users where username='GAME';

显示用户的PROFILE
select profile from dba_users where username='GAME';


2、表

查看用户下所有的表
SQL>select * from user_tables;

查看名称包含log字符的表
SQL>select object_name,object_id from user_objects
where instr(object_name,'LOG')>0;

查看某表的创建时间
SQL>select object_name,created from user_objects where object_name=upper('&table_name');

查看某表的大小
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments
where segment_name=upper('&table_name');

查看放在ORACLE的内存区里的表
SQL>select table_name,cache from user_tables where instr(cache,'Y')>0;

3、索引

查看索引个数和类别
SQL>select index_name,index_type,table_name from user_indexes order by table_name;

查看索引被索引的字段
SQL>select * from user_ind_columns where index_name=upper('&index_name');

查看索引的大小
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments
where segment_name=upper('&index_name');

4、序列号

查看序列号，last_number是当前值
SQL>select * from user_sequences;

5、视图

查看视图的名称
SQL>select view_name from user_views;

查看创建视图的select语句
SQL>set view_name,text_length from user_views;
SQL>set long 2000; 说明：可以根据视图的text_length值设定set long 的大小
SQL>select text from user_views where view_name=upper('&view_name');

6、同义词

查看同义词的名称
SQL>select * from user_synonyms;

7、约束条件

查看某表的约束条件
SQL>select constraint_name, constraint_type,search_condition, r_constraint_name
from user_constraints where table_name = upper('&table_name');

SQL>select c.constraint_name,c.constraint_type,cc.column_name
from user_constraints c,user_cons_columns cc
where c.owner = upper('&table_owner') and c.table_name = upper('&table_name')
and c.owner = cc.owner and c.constraint_name = cc.constraint_name
order by cc.position;

8、存储函数和过程

查看函数和过程的状态
SQL>select object_name,status from user_objects where object_type='FUNCTION';
SQL>select object_name,status from user_objects where object_type='PROCEDURE';

查看函数和过程的源代码
SQL>select text from all_source where owner=user and name=upper('&plsql_name');
--------------------------------------------------oracle 查询 表字段 以及字段 数据类型 -----------------------------------------

第一种

select cname from col where tname='EMP';

第二种

select column_name from user_tab_columns where table_name='EMP';

 

 

介绍  如果查询数据的  字段数据类型

select data_type from user_tab_columns where table_name='EMP';

 两个一起查
select data_type,column_name from user_tab_columns where table_name='EMP';

--------------------------------------------查询 字段注释---------------------------------------------

select * from user_col_comments ;//所有的注释
select * from user_col_comments where table_name='你的表(emp)' ;//指定表的注释