Oracle Solution for Error ora-30756

ORA-30756: cannot create column or table of type that contains a supertype attribute

What triggered the Error:

The user tried to create a column or table of an object type that contains a supertype attribute. This is not supported because it leads to infinite recursion in our current storage model. Note that creating a column of a type implies that we create columns corresponding to all subtype attributes as well.

What should we do to fix it:

Change the type definition to contain a supertype REF attribute instead of the supertype object attribute.