ORA-01451: column to be modified to NULL cannot be modified to NULL - Oracle Database 12c Error Msg

In this video we are going to see how to fix below Oracle Database 12c Error Message. ORA-01451: column to be modified to NULL cannot be modified to NULL Cause: the column may already allow NULL values, the NOT NULL constraint is part of a primary key or check constraint. Action: if a primary key or check constraint is enforcing the NOT NULL constraint, then drop that constraint. #database