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AL16UTF16 to US7ASCII

Declan Heerey
Frequent Advisor

AL16UTF16 to US7ASCII

I have exported a dump from a 9i database with a AL16UTF16 character set

I'm importing this to a 9i database with a US7ASCII character set

Import summary:
Export file created by EXPORT:V09.02.00 via conventional path
import done in US7ASCII character set and UTF8 NCHAR character set
export server uses AL16UTF16 NCHAR character set (possible ncharset conversion)

I've encountered several errors, can someone tell me if the character set AL16UTF16 can be converted back into it's predecessor 7bit US7ASCII

Thanks in advance

Declan
2 REPLIES
Peter Godron
Honored Contributor

Re: AL16UTF16 to US7ASCII

Declan,
from 9i onwards the NCHAR type is restricted to AL16UTF16 and UTF8 char sets.
Your db creation script defines the char set to be used.
Regards
Indira Aramandla
Honored Contributor

Re: AL16UTF16 to US7ASCII

Hi Declan,

Import and export are client products, and will therefore translate characters from the database character set to that defined by NLS_LANG.

The character set used for the export will be stored in the export file and, when the file is imported, the import will check the character set that was used. If it is different to that defined by NLS_LANG at the import site, the characters will be translated to the import character set and then, if necessary, to the database character set.

NLS_NCHAR_CHARACTERSET is defined when the database is created and specified with the CREATE DATABASE command. The NLS_NCHAR_CHARACTERSET defaults to AL16UTF16 if nothing is specified.

From 9i onwards the NLS_NCHAR_CHARACTERSET can have only 2 values:
UTF8 or AL16UTF16. Both UTF8 and AL16UTF16 are unicode charactersets, so they can store whatever you had as NLS_NCHAR_CHARACTERSET in 8(i).

If you are not using N-types then keep the default AL16UTF16 or use UTF8. There is NO problem at all with AL16UTF16 because you are simply not using it and ORACLE strongly advices one to the keep the default AL16UTF16 NLS_NCHAR_CHARACTERSET.

To change from AL16UTF16 to UTF8 ou cn do by using Database Character Set Migration Utility (csminst.sql ) located in $ORACLE_HOME/rdbms/admin directory.

If you really need to change from AL16UTF16 to UTF8, log a tar so that we can assist you.

Indira A
Never give up, Keep Trying