Oracle Userenv functions, Sys_context (NLS) __ static functions

Userenv in Oracle ()

Oracle Userenv functions, Sys_context

Get session ID with Userenv, then connect v$transaction connection v$session, check current transaction number with session ID

Select T.xid from V$transaction t join v$session s on t.addr = s.taddr where s.sid = Userenv (' Sid ')

1, USERENV (OPTION)
Returns the current session information.
Option= ' Isdba ' is true if it is currently a DBA role, or false.
option= ' LANGUAGE ' returns the character set of the database.
Option= ' SESSIONID ' is the current session identifier.
option= ' ENTRYID ' returns an auditable session identifier.
option= ' LANG ' returns the ISO denoted for the session language name.
option= ' INSTANCE ' returns the current instance.
option= ' terminal ' Returns the current computer name
SELECT USERENV (' LANGUAGE ') from DUAL;

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

Oracle dual is a virtual table that forms the syntax rules for SELECT, and Oracle guarantees that there is always only one record in dual.

SQL language is not a universal program statement, it can interact with the outside only select update Insert Delete, all four sentences have a table, what to do without the table. Then use the dual watch.