userenv() 和sys_context()

1.USEREVN()
返回當前使用者環境的資訊,opt可以是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE

1.ISDBA 檢視當前使用者是否是DBA如果是則返回true
SQL> select userenv('isdba') from dual;

USEREN
------
FALSE

2.SESSION 返回會話標誌
SQL> select userenv('sessionid') from dual;

USERENV('SESSIONID')
--------------------
152

4.ENTRYID 返回會話入口標誌
SQL> select userenv('entryid') from dual;

USERENV('ENTRYID')
------------------
0

5.INSTANCE 返回當前INSTANCE的標誌
SQL> select userenv('instance') from dual;

USERENV('INSTANCE')
-------------------
1

6.LANGUAGE 返回當前環境變數
SQL> select userenv('language') from dual;

USERENV('LANGUAGE')
----------------------------------------------------
SIMPLIFIED CHINESE_CHINA.ZHS16GBK

7.LANG 返回當前環境的語言的縮寫
SQL> select userenv('lang') from dual;

USERENV('LANG')
----------------------------------------------------
ZHS

8.TERMINAL 返回使用者的終端或機器的標誌
SQL> select userenv('terminal') from dual;

USERENV('TERMINA
----------------
GAO

9.VSIZE(X) 返回X的大小(位元組)數
SQL> select vsize(user),user from dual;

VSIZE(USER) USER
----------- ------------------------------
6 SYSTEM

2.sys_context

　　select
　　SYS_CONTEXT('USERENV','TERMINAL') terminal,
　　SYS_CONTEXT('USERENV','LANGUAGE') language,
　　SYS_CONTEXT('USERENV','SESSIONID') sessionid,
　　SYS_CONTEXT('USERENV','INSTANCE') instance,
　　SYS_CONTEXT('USERENV','ENTRYID') entryid,
　　SYS_CONTEXT('USERENV','ISDBA') isdba,
　　SYS_CONTEXT('USERENV','NLS_TERRITORY') nls_territory,
　　SYS_CONTEXT('USERENV','NLS_CURRENCY') nls_currency,
　　SYS_CONTEXT('USERENV','NLS_CALENDAR') nls_calendar,
　　SYS_CONTEXT('USERENV','NLS_DATE_FORMAT') nls_date_format,
　　SYS_CONTEXT('USERENV','NLS_DATE_LANGUAGE') nls_date_language,
　　SYS_CONTEXT('USERENV','NLS_SORT') nls_sort,
　　SYS_CONTEXT('USERENV','CURRENT_USER') current_user,
　　SYS_CONTEXT('USERENV','CURRENT_USERID') current_userid,
　　SYS_CONTEXT('USERENV','SESSION_USER') session_user,
　　SYS_CONTEXT('USERENV','SESSION_USERID') session_userid,
　　SYS_CONTEXT('USERENV','PROXY_USER') proxy_user,
　　SYS_CONTEXT('USERENV','PROXY_USERID') proxy_userid,
　　SYS_CONTEXT('USERENV','DB_DOMAIN') db_domain,
　　SYS_CONTEXT('USERENV','DB_NAME') db_name,
　　SYS_CONTEXT('USERENV','HOST') host,
　　SYS_CONTEXT('USERENV','OS_USER') os_user,
　　SYS_CONTEXT('USERENV','EXTERNAL_NAME') external_name,
　　SYS_CONTEXT('USERENV','IP_ADDRESS') ip_address,
　　SYS_CONTEXT('USERENV','NETWORK_PROTOCOL') network_protocol,
　　SYS_CONTEXT('USERENV','BG_JOB_ID') bg_job_id,
　　SYS_CONTEXT('USERENV','FG_JOB_ID') fg_job_id,
　　SYS_CONTEXT('USERENV','AUTHENTICATION_TYPE') authentication_type,
　　SYS_CONTEXT('USERENV','AUTHENTICATION_DATA') authentication_data
　　from dual;