oracle用户环境查询语句和函数

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做任何事情，都要知己知彼，至少得知道自己所处的环境，下面我

就介绍一下了解登录用户环境的oracle查询语句。

下面就是我在自己电脑上的一些实验；

SQL> --显示当前用户名；
SQL> show user;
USER 为 "SYS"
SQL> --显示当前实例名；
SQL> select instance_name from v$instance;

INSTANCE_NAME                                              

                   
----------------                                           

                   
orcl                                        
SQL> --显示当前实例名另外一种方法；         
SQL> select name from v$database;

NAME                                                       

                   
---------                                                  

                   
ORCL                                                       

                   

SQL> --查看现在的启动状态；
SQL> select status from v$instance;

STATUS                                                     

                   
------------                                               

                   
OPEN                                                       

                   

SQL> --使用USEREVN函数来返回当前用户的环境信息；
SQL> --查看当前用户是否是DBA如果是则返回true，我测试了后发

现只有sys用户是TRUE，其它都为FALSE；
SQL> select userenv('isdba') from dual;

USEREN                                                     

                   
------                                                     

                   
TRUE                                                       

                   
返回会话标志
SQL> select userenv('sessionid') from dual;

USERENV('SESSIONID')                                       

                   
--------------------                                       

                   
          4294967295                                       

                   
返回会话人口标志
SQL> select userenv('entryid') from dual;

USERENV('ENTRYID')                                         

                   
------------------                                         

                   
                 0                                         

                   
返回当前INSTANCE的标志
SQL> select userenv('instance') from dual;

USERENV('INSTANCE')                                        

                   
-------------------                                        

                   
                  1                                        

                   
返回当前环境变量
SQL> select userenv('language') from dual;

USERENV('LANGUAGE')                                        

                   
----------------------------------------------------       

                   
SIMPLIFIED CHINESE_CHINA.ZHS16GBK                          

                   
返回当前环境的语言的缩写
SQL> select userenv('lang') from dual;

USERENV('LANG')                                            

                   
----------------------------------------------------       

                   
ZHS                                                        

                   

返回用户的终端或机器的标志
SQL> select userenv('terminal') from dual;

USERENV('TERMINAL')                                        

                   
------------------------------                             

                   
BK-FDA996F2E2E9                                            

                   

返回X的大小(字节)数，这里sys表示3个字节；
SQL> select vsize(user),user from dual;

VSIZE(USER) USER                                           

                   
----------- ------------------------------                 

                   
          3 SYS