How to save unicode data to oracle?

Question

I am trying to save unicode data (greek) in oracle database (10 g). I have created a simple table:

I understand that NVARCHAR2 always uses UTF-16 encoding

Answer 1

Solution: set NLS_LANG!

Details: I just had the same problem, and actually had exact the same situation as described in Sergey Bazarnik's investigation. Using bind variables it works, and without them it doesn't.

The SOLUTION is to set NLS_LANG in proper place. Since I have Windows server I set it in windows registry under HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ORACLE\KEY_OraClient11g_home1

Please note that regitry location may difer so the easiest way is to search registry for "ORACLE_HOME" string. Also other systems like Linux, Unix can set this on different way (export NLS_LANG ...)

In my case I put "NLS_LANG"="CROATIAN_CROATIA.UTF8". Since I had no that variable set it went to default value. After changing registry you should restart process. In my case I restarted IIS.

Regarding reason why it works with bind variables may be because it actually happens on server side, while without it actually happens on client side. So even that DB can insert proper values - before that happens, client does the unwanted corrections, since it thinks that is should do that. That is because NLS_LANG defaults to simpler code page. But instead of doing useful task, that creates a problem, which (as shown in investigation looks hard to understand).

In case you have multiple oracle versions, be sure to correct all versions in registry (in my case Oracle 10 had valid setting, but Oracle 11 had no NLS_LANG set at all).