Re: Non Identifying Foreign Key Relationships

I apologize for wasting your time reading this post... I retested after seeing your reply and noticed that I had forgotten the cardinal rule that '' and NULL are not the same! I put NULL into the insert statements for the column in question and it worked as expected.

Thank you for your time,

Karen Grose
kgrose(at)vigilos(dot)com
-----Original Message-----
From: Stephan Szabo [mailto:sszabo(at)megazone23(dot)bigpanda(dot)com]
Sent: Monday, March 24, 2003 4:36 PM
To: Karen Grose
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Non Identifying Foreign Key Relationships

On Mon, 24 Mar 2003, Karen Grose wrote:

> 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?

That should work I think, can you give a standalone example script?