Multibyte language support on Oracle Database

If the Oracle Database was originally installed as a multibyte database, the following values must be set before you begin the upgrade:

• The instance character must be set to UTF-8 or UTF-16. If you do not select a UTF-8 or UTF-16 character set, a multibyte character in the database is shown as a question mark.
• The NLS_LENGTH_SEMANTICS parameter must be set to CHAR. If you use BYTE instead of CHAR, the platform does not run the length operations correctly and data can be lost.
• The block size must be set to at least 16K.