nls_instance_parameter 中NLS_LANG是否受OS環(huán)境變量影響測試

2019-11-09 13:34:28

字體：大中小

供稿：網(wǎng)友

nls_instance_parameters取值與v$system_parameter一致,下面讓我們看一下v$system_parameter 在官方文檔的定義：V$SYSTEM_PARAMETER displays information about the initialization parameters that are currently in effect for the instance.A new session inherits parameter values from the instance-wide values.從這里，我們可知，nls_instance_parameters的值有參數(shù)文件決定，那么會不會受到環(huán)境變量的影響哪？經(jīng)驗證，是不會的！過程如下：首先，我們來看一下NLS_LANGUAGE的取值

sys>select parameter,value from nls_instance_parameters where parameter='NLS_LANGUAGE';         PARAMETER              VALUE  ------------------------------ ------------------------------  NLS_LANGUAGE               SIMPLIFIED CHINESE關(guān)閉數(shù)據(jù)庫，然后修改環(huán)境變量NLS_LANG:sys>shutdown immediate  Database closed.  Database dismounted.  Oracle instance shut down.  sys>exit  Disconnected from Oracle Database 11g EnterPRise Edition Release 11.2.0.3.0 - 64bit Production  With the Partitioning, OLAP, Data Mining and Real application Testing options  [oracle@oadata ~]$ vi .bash_profile  [oracle@oadata ~]$ . .bash_profile  [oracle@oadata ~]$ set | grep NLS  NLS_DATE_FORMAT='YYYY-MM-DD HH24:MI:SS'NLS_LANG=AMERICAN_AMERICA.AL32UTF8[oracle@oadata ~]$ sqlplus / as sysdba         SQL*Plus: Release 11.2.0.3.0 Production on Wed Sep 18 16:01:00 2013         Copyright (c) 1982, 2011, Oracle.  All rights reserved.         Connected to an idle instance.         SQL> startup  ORACLE instance started.         Total System Global Area 2137886720 bytes  Fixed Size          2230072 bytes  Variable Size        1342179528 bytes  Database Buffers      788529152 bytes  Redo Buffers            4947968 bytes  Database mounted.  Database opened.  SQL> select parameter,value from nls_instance_parameters where parameter='NLS_LANGUAGE';         PARAMETER              VALUE  ------------------------------ ------------------------------  NLS_LANGUAGE               SIMPLIFIED CHINESE可見，nls_instance_parameters只受參數(shù)文件的影響，而不受環(huán)境變量影響。nls_session_parameters 它的查詢結(jié)果默認會從nls_instance_parameters繼承，但是如果，我們在環(huán)境變量或者通過ALTER SESSION 改變了nls的相關(guān)參數(shù)，則會覆蓋默認值。例如，當環(huán)境變量NLS_LANG=AMERICAN_AMERICA.AL32UTF8SQL> select parameter,value from nls_session_parameters where parameter='NLS_LANGUAGE';         PARAMETER              VALUE  ------------------------------ ------------------------------  NLS_LANGUAGE               AMERICAN當環(huán)境變量NLS_LANG='SIMPLIFIED CHINESE_CHINA.AL32UTF8'SQL> select parameter,value from nls_session_parameters where parameter='NLS_LANGUAGE';         PARAMETER              VALUE  ------------------------------ ------------------------------  NLS_LANGUAGE               SIMPLIFIED CHINESE