I am in the process of upgrading to Postgresql 7.3.1 from 7.1. While testing the results of the conversion, I have run into an issue with establishing non-identifying or optional foreign key relationships.
1) My child table definition contains a foreign key that references the parent primary key
2) The child table column referencing the parent is not part of the child primary key
3) The child table column referencing the parent is defined with NULLS allowed
The test that I performed tried to load NULL values into the column and it failed with a referential integrity violation stating that the parent must exist. How do I accomplish creating this type of constraint within Postgresql version 7.3?
Thank you in advance for your help,
