SYS_CONTEXT() Function

1> USERENV(OPTION)
　　返回当前的会话信息.
　　OPTION='ISDBA'若当前是DBA角色,则为TRUE,否则FALSE.
　　OPTION='LANGUAGE'返回数据库的字符集.
　　OPTION='SESSIONID'为当前会话标识符.
　　OPTION='ENTRYID'返回可审计的会话标识符.
　　OPTION='LANG'返回会话语言名称的ISO简记.
　　OPTION='INSTANCE'返回当前的实例.
   OPTION='terminal'返回当前计算机名

　　SQL>

     SELECT USERENV('LANGUAGE') FROM DUAL;

2> SYS_CONTEXT()

 

select SYS_CONTEXT('USERENV', 'TERMINAL') terminal,
       SYS_CONTEXT('USERENV', 'LANGUAGE') language,
       SYS_CONTEXT('USERENV', 'SESSIONID') sessionid, --Be equal to AUDSID column of V$SESSION,
       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