【Oracle】详解Oracle中NLS_LANG变量的使用
目录结构：
1，关于NLS_LANG参数
Oracle provides Globalization Support that enables users to interact with a database in their own language, as defined by the NLS_LANG parameter. When you install Oracle Database Client components, Oracle Universal Installer sets the NLS_LANG parameter in the registry.
The locale setting of your operating system determines the value of the NLS_LANG parameter at installation. Table C-1 lists the operating system locale and NLS_LANG value mappings.
The NLS_LANG parameter is stored in the registry under the HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOMEID\NLS_LANG subkey, where ID is the unique number identifying the Oracle home.
The NLS_LANG parameter uses the following format:
NLS_LANG = LANGUAGE_TERRITORY.CHARACTER_SET
Oracle提供全球化的支持，通过定义NLS_LANG参数能够让用户用他们自己的语言使用数据库。当安装Oracle数据库客户端的时候，安装程序通常会在注册表中设置NLS_LANG参数。
在安装中，操作系统的区域设置会决定NLS_LANG参数的值。表C-1列出了操作系统区域和NLS_LANG的对照表。
NLS_LANG参数被存储在注册表中的HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOMEID\NLS_LANG子项下，其中ID是识别Oracle home的唯一数字。
NLS_LANG参数使用如下的格式：
NLS_LANG = LANGUAGE_TERRITORY.CHARACTER_SET
where:
| Parameter | Description |
|---|---|
LANGUAGE |
Specifies the language and conventions for displaying messages, day name, and month name. |
TERRITORY |
Specifies the territory and conventions for calculating week and day numbers. |
CHARACTER_SET |
Controls the character set used for displaying messages. |
2 NSL_LANG常用的值
Table C-1 lists commonly used NLS_LANG values for various operating system locales:
Table C-1 NLS_LANG Parameter Values
| Operating System Locale | NLS_LANG Value |
|---|---|
| Arabic (U.A.E.) | ARABIC_UNITED ARAB EMIRATES.AR8MSWIN1256 |
| Bulgarian | BULGARIAN_BULGARIA.CL8MSWIN1251 |
| Catalan | CATALAN_CATALONIA.WE8MSWIN1252 |
| Chinese (PRC) | SIMPLIFIED CHINESE_CHINA.ZHS16GBK |
| Chinese (Taiwan) | TRADITIONAL CHINESE_TAIWAN.ZHT16MSWIN950 |
| Croatian | CROATIAN_CROATIA.EE8MSWIN1250 |
| Czech | CZECH_CZECH REPUBLIC.EE8MSWIN1250 |
| Danish | DANISH_DENMARK.WE8MSWIN1252 |
| Dutch (Netherlands) | DUTCH_THE NETHERLANDS.WE8MSWIN1252 |
| English (United Kingdom) | ENGLISH_UNITED KINGDOM.WE8MSWIN1252 |
| English (United States) | AMERICAN_AMERICA.WE8MSWIN1252 |
| Estonian | ESTONIAN_ESTONIA.BLT8MSWIN1257 |
| Finnish | FINNISH_FINLAND.WE8MSWIN1252 |
| French (Canada) | CANADIAN FRENCH_CANADA.WE8MSWIN1252 |
| French (France) | FRENCH_FRANCE.WE8MSWIN1252 |
| German (Germany) | GERMAN_GERMANY.WE8MSWIN1252 |
| Greek | GREEK_GREECE.EL8MSWIN1253 |
| Hebrew | HEBREW_ISRAEL.IW8MSWIN1255 |
| Hungarian | HUNGARIAN_HUNGARY.EE8MSWIN1250 |
| Icelandic | ICELANDIC_ICELAND.WE8MSWIN1252 |
| Indonesian | INDONESIAN_INDONESIA.WE8MSWIN1252 |
| Italian (Italy) | ITALIAN_ITALY.WE8MSWIN1252 |
| Japanese | JAPANESE_JAPAN.JA16SJIS |
| Korean | KOREAN_KOREA.KO16MSWIN949 |
| Latvian | LATVIAN_LATVIA.BLT8MSWIN1257 |
| Lithuanian | LITHUANIAN_LITHUANIA.BLT8MSWIN1257 |
| Norwegian | NORWEGIAN_NORWAY.WE8MSWIN1252 |
| Polish | POLISH_POLAND.EE8MSWIN1250 |
| Portuguese (Brazil) | BRAZILIAN PORTUGUESE_BRAZIL.WE8MSWIN1252 |
| Portuguese (Portugal) | PORTUGUESE_PORTUGAL.WE8MSWIN1252 |
| Romanian | ROMANIAN_ROMANIA.EE8MSWIN1250 |
| Russian | RUSSIAN_CIS.CL8MSWIN1251 |
| Slovak | SLOVAK_SLOVAKIA.EE8MSWIN1250 |
| Spanish (Spain) | SPANISH_SPAIN.WE8MSWIN1252 |
| Swedish | SWEDISH_SWEDEN.WE8MSWIN1252 |
| Thai | THAI_THAILAND.TH8TISASCII |
| Spanish (Mexico) | MEXICAN SPANISH_MEXICO.WE8MSWIN1252 |
| Spanish (Venezuela) | LATIN AMERICAN SPANISH_VENEZUELA.WE8MSWIN1252 |
| Turkish | TURKISH_TURKEY.TR8MSWIN1254 |
| Ukrainian | UKRAINIAN_UKRAINE.CL8MSWIN1251 |
| Vietnamese | VIETNAMESE_VIETNAM.VN8MSWIN1258 |
3 在MS-DOS模式和Batch模式中设置NLS_LANG
Before you can use Oracle utilities such as SQL*Plus, SQL Loader, Import, and Export in MS-DOS mode, make sure that you have set the character set field of the NLS_LANG parameter for the session to the correct value.
This is required because MS-DOS mode uses, with a few exceptions, a different character set (or code-page) from Windows (ANSI code-page), and the default Oracle home NLS_LANG parameter in the registry is always set to the appropriate Windows code-page. If you do not set the NLS_LANG parameter for the MS-DOS mode session correctly, incorrect character conversion can corrupt error messages and data.
For Japanese, Korean, Simplified Chinese, and Traditional Chinese, the MS-DOS code-page is identical to the ANSI code-page. In this case, you do not need to set the NLS_LANG parameter in MS-DOS mode.
Similarly, in batch mode, set the correct character set value of NLS_LANG by inserting a SET NLS_LANG command at the start of the batch procedure, according to the character set of the files to be processed in the procedure.
在你使用Oracle应用之前，比如在MS-DOS模式中使用SQL*Plus,SQL Loader,Import,和Export，确保你已经在本次会话中正确的设置了字符集属性和NLS_LANG参数属性。
这是必须的，因为MS-DOS模式的使用会带有一些的来着Windows(ANSI code-page)的不同字符集设置的异常，在注册表中默认的Oracle home NLS_LANG参数总是会被设置成适合Windows code-page的值。
如果你在MS-DOS模式中不正确的设置NLS_LANG参数的值，那么错误的字符转换将会损坏信息和数据。
对于日文，韩文，简体中文和繁体中文，MS—DOS code-page 和ANSI code-page的值一样。在这种情况下，你不需要在MS-DOS模式中设置NLS_LANG参数的值。
同样的，在Batch模式中，根据程序运行过程中被处理的文件字符，通过插入SET LANG_LANG 命令设置正确的NLS_LANG值。
Table C-2 lists the Oracle character sets that correspond to the MS-DOS mode for various operating system locales:
Table C-2 Oracle Character Sets for Operating System Locales
| Operating System Locale | Character Set |
|---|---|
| Catalan | WE8PC850 |
| Chinese (PRC) | ZHS16GBK |
| Chinese (Taiwan) | ZHT16MSWIN950 |
| Czech | EE8PC852 |
| Danish | WE8PC850 |
| Dutch | WE8PC850 |
| English (United Kingdom) | WE8PC850 |
| English (United States) | US8PC437 |
| Finnish | WE8PC850 |
| French | WE8PC850 |
| German | WE8PC850 |
| Greek | EL8PC737 |
| Hungarian | EE8PC852 |
| Italian | WE8PC850 |
| Japanese | JA16SJIS |
| Korean | KO16MSWIN949 |
| Norwegian | WE8PC850 |
| Polish | EE8PC852 |
| Portuguese | WE8PC850 |
| Romanian | EE8PC852 |
| Russian | RU8PC866 |
| Slovak | EE8PC852 |
| Slovenian | EE8PC852 |
| Spanish | WE8PC850 |
| Swedish | WE8PC850 |
| Turkish | TR8PC857 |
| Catalan | WE8PC850 |
4，注册表中NLS_LANG和系统环境变量中的NLS_LANG
当用户安装好Oracle客户端后会在注册表中出现NLS_LANG的注册信息，在操作系统的环境变量中用户也可以设置自己的NLS_LANG的值。
但是需要注意：
注册表中的NLS_LANG是用于对应Oracle数据库与windows 的code-page值的，这个值是在安装的过程中自动添加的，一般不要去修改，如果修改后NLS_LANG的值与code-page的值不对应的话，会出现不同字符的异常。
系统环境变脸中NLS_LANG是用于对应Oracle数据显示的，这个值在安装完成后可能会有，也可能没有，是可以修改的，如果希望以中文显示则修改为 NLS_LANG=SIMPLIFIED CHINESE_CHINA.ZHS16GBK ，也可以是英文的 NLS_LANG=AMERICAN_AMERICA.UTF8 ，建议在使用Oracle数据库之间将这里的NLS_LANG设置为英文显示。
