| From: | "Wm(dot) G(dot) Urquhart" <wgu(at)wurquhart(dot)co(dot)uk> |
|---|---|
| To: | PostgreSQL General Forum <pgsql-general(at)postgresql(dot)org> |
| Subject: | Referential Integrity. |
| Date: | 2002-05-20 11:53:24 |
| Message-ID: | Pine.LNX.4.44.0205201243330.13618-100000@mailer.wurquhart.co.uk |
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| Lists: | pgsql-general |
Hi All,
After yesterday's disaster I've taken this opportunity to rebuild by
database from the ground up. As part of this I want to be able to set a
column to have a default of 0 (easy enough) but this column is a Foreign
Key to another table whos referenced column value starts at 1.
Is there anyway I can write a FK Constraint that will allow this? I don't
want to have to enter a row in the referenced table since since it in turn
has not null constraints on it.
I really want a way to allow 0 as a legitimate value, to assist in the
predicates of a SELECT. It is possible to get to and modify the code that
PostgreSQL creates to enforce this I assume via CREATE CONSTRAINT TRIGGER?
Any help would be appreciated.
--
Regards,
Wm. G. Urquhart
Custom Software Solutions
http://www.wurquhart.co.uk
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