From: Jon Horsman <horshaq@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Foreign Unique Constraint
Date: Tue, 27 Mar 2007 09:21:44 -0400
Message-ID: <4f4c2a010703270621h5137a4e5rb515a9be9034a543@mail.gmail.com> (raw)
I was wondering if someone could help point me in the right direction
w.r.t. foreign unique constraints. I'm working on a legacy database
and have a new requirement and am not sure how to do it.
I have something like this
create table table1 (
id SERIAL PRIMARY KEY
extension UNIQUE,
<other fields>
)
create table table2 (
id SERIAL PRIMARY KEY
extension UNIQUE,
<different fields>
)
Basically table 1 and table 2 both have the concept of an extension
that must be unique but the rest of the info in the tables are
different. I need to ensure that if i add an entry to table 1 with
extension 1000 that it will fail if there is already an entry in
table2 with the same extension.
Essentially i need to do something like the following but i get errors
saying this can't be done.
alter table table1 add check (extension <> table2.extension);
It should be noted i am using pg version 7.4.13 and this can't change.
Thanks for any help you can offer.
Jon.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: horshaq@gmail.com
Subject: Re: Foreign Unique Constraint
In-Reply-To: <4f4c2a010703270621h5137a4e5rb515a9be9034a543@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox