database character set

A character set determines what languages can be represented in the database.
Oracle recommends Unicode AL32UTF8 as the database character set. Unicode is the universal character set that supports most of the currently spoken languages of the world.

As AL32UTF8 is a multibyte character set, database operations on character data may be slightly slower when compared to single-byte database character sets, such as WE8MSWIN1252.


AL16UTF16 is only available as a choice for the National Character Set. If you want the database itself to be Unicode you can choose from UTF8 and AL32UTF8. AL32UTF8 is generally preferred because of its ongoing support of the Unicode Standard.

In most cases about 99% of the time, if you are using AL32UTF8 for your database character set, you wont make use of your national character set at all, so it doesnt matter.

If your database character set were AL32UTF8, there would be no advantage of using UTF-8 as your national character set. Occasionally, there may be a benefit to using UTF-16 for your national character set because that would potentially allow you to store Asian characters in less space (most Asian characters require 3 bytes to encode in UTF-8 and 2 bytes to encode in UTF-16).

select * from nls_database_parameters where parameter='NLS_CHARACTERSET';

SELECT * FROM NLS_DATABASE_PARAMETERS;

SELECT UNIQUE VALUE FROM V$NLS_VALID_VALUES WHERE PARAMETER ='CHARACTERSET' AND isdeprecated = 'FALSE';

SELECT NLS_CHARSET_ID('WE8MSWIN1252') FROM dual;

SELECT * FROM nls_database_parameters WHERE parameter LIKE '%CHARACTERSET%';

select * from nls_database_parameters  where parameter='NLS_CHARACTERSET';

SELECT * FROM NLS_DATABASE_PARAMETERS;