ORA-12717: Cannot issue ALTER DATABASE NATIONAL CHARACTER SET when NCLOB, NCHAR or NVARCHAR2 data exists

ORA-12717: Cannot issue ALTER DATABASE NATIONAL CHARACTER SET when NCLOB, NCHAR or NVARCHAR2 data exists


Cause:


NCLOB, NCHAR or NVARCHAR2 data changed the representation to Unicode when converting to a multibyte character set and must be migrated.



Action:


Remove NCLOB, NCHAR or NVARCHAR2 data as listed in the alert file. The above type data can be migrated by methods such as import/export.