Setting NLS_LANG for Oracle

NLS_LANG= language_territory.character set

Example:
export NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1

Setting NLS_LANG tells Oracle what characterset the client is using so Oracle can do conversion if needed from client’s characterset to the database characterset and setting this parameter on the client does not change the client’s characterset. Setting Language and Territory in NLS_LANG has nothing to do with storing characters in database, it’s controlled by the characterset and of course if the database can store that characterset.

To check session NLS session parameters, note this doesn’t return the characterset set by NLS_LANG

SELECT * FROM NLS_SESSION_PARAMETERS;
SELECT USERENV ('language') FROM DUAL;

To find the NLS_LANG of your database one can run the following SQL:
SQL> SELECT * from NLS_DATABASE_PARAMETERS WHERE parameter IN ( 'NLS_LANGUAGE', 'NLS_TERRITORY', 'NLS_CHARACTERSET');

PARAMETER VALUE
—————————— —————————————-
NLS_LANGUAGE AMERICAN
NLS_TERRITORY AMERICA
NLS_CHARACTERSET WE8MSWIN1252

To get the possible value for language, territory and characterset you can check the view V$NLS_VALID_VALUES.
– parameter – possible values LANGUAGE, TERRITORY, CHARACTERSET

SELECT parameter, value FROM V$NLS_VALID_VALUES;

To change the client language

export NLS_LANG=BELGIUM_.WE8ISO8859P1
To change the client territory
export NLS_LANG=_BELGIUM.WE8ISO8859P1
To change the client characterset
export NLS_LANG=.AL32UTF8


Amin Jaffer