How to fix the Oracle error ORA-12717: Cannot issue ALTER DATABASE NATIONAL CHARACTER SET when NCLOB, NCHAR or NVARCHAR2 data exists?

In this post, you’ll learn more about the Oracle ErrorORA-12717: Cannot issue ALTER DATABASE NATIONAL CHARACTER SET when NCLOB, NCHAR or NVARCHAR2 data exists with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

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

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

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

How to fix the Error ORA-12717: Cannot issue ALTER DATABASE NATIONAL CHARACTER SET when NCLOB, NCHAR or NVARCHAR2 data exists ?

You can fix this error in Oracle by following the below steps

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.