dipendence between NLS_CHARACTERSET and NLS_NCHAR_CHARACTERSET parameters

I created my database (Oracle 9.0.1.3 on SuSE SLES7) with NLS_CHARACTERSET=US7ASCII and NLS_NCHAR_CHARACTERSET=AL16UTF16 because my intention was to use NVARCHAR2 columns for storing multilanguage strings.

I thought these two parameters were independent from each other. But then I came into "bug" 2858947 (actually, not a bug but an expected behaviour):

"When a string literal is included in a query and the query is submitted through a client-side tool such as SQL*Plus, all the queries are encoded in the client's character set and then converted to the server's database character set before processing. Therefore, data loss can occur if the string literal cannot be converted to the server database character set."

This make NVARCHAR2 columns absolutely usable for me. But, as I understood correctly the above paragraph, even if my database were created with WE8ISO8859P1 charset I would not have been able to store anything but WE8IS8859P1 strings in NVARCHAR2 columns, because all string literals would have been "converted to the server's database character set before processing". So what is the aim of NVARCHAR2 datatype? I'm confused.

Kind regards,

-- 
Cris Carampa (spamto:cris119_at_operamail.com)

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