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

　　SELECT USERENV('LANGUAGE') FROM DUAL;

 

 

--当前SID

select distinct sid from v$mystat;

select sid from v$session where audsid = userenv('SESSIONID');

 

2、返回系统会话信息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 ;

　　其中，第二个参数的可选值如下：

　　AUTHENTICATION_DATA

　　Data being used to authenticate the login user. For X.503 certificate authenticated sessions, this field returns the context of the certificate in HEX2 format.

　　Note: You can change the return value of the AUTHENTICATION_DATA attribute using the length parameter of the syntax. Values of up to 4000 are accepted. This is the only attribute of USERENV for which Oracle implements such a change.

　　AUTHENTICATION_TYPE

　　How the user was authenticated:

　　DATABASE: username/password authentication

　　OS: operating system external user authentication

　　NETWORK: network protocol or ANO authentication

　　PROXY: OCI proxy connection authentication