ORA-40609
Cannot create JSON Relational Duality View 'string': foreign key column 'string' of table 'string' should be part of the primary or unique key of the same table, or it should not be selected to construct subobject 'string'.
Cause
The foreign key column could only be selected if it was also part of a primary or unique key of the same table, which is required to uniquely identify the Duality View objects.
Action
Add the foreign key columns to the primary or unique key of the same table, or remove it from the select statement.