Oracle Solution for Error ora-30401

ORA-30401: JOIN KEY columns must be non-null

What triggered the Error:

The dimension statement failed because the column(s) in the JOIN KEY clause permitted NULL values. The JOIN KEY columns are related to the columns of the dimension's skip levels in one or both of the following ways: *1. A skip level is defined over one or more of the JOIN KEY columns. *2. The attribute clauses of a skip level determine one or more of the JOIN KEY columns.

What should we do to fix it:

Modify the JOIN KEY columns so that they do not allow NULL values.