Oracle全球化方面支持的官方文档

http://docs.oracle.com/cd/B19306_01/server.102/b14225/toc.htm
http://docs.oracle.com/cd/B19306_01/server.102/b14225/ch6unicode.htm http://docs.oracle.com/cd/B19306_01/server.102/b14225/ch7progrunicode.htm http://docs.oracle.com/cd/B19306_01/server.102/b14225/ch8gdk.htm
字符集相关查询，

select * from nls_database_parameters -- DB servier

select * from nls_instance_parameters -- DB client

select * from nls_session_parameters -- user session

SELECT SYS_CONTEXT ('USERENV', 'LANGUAGE')     FROM DUAL;