From: Gary Stainburn <gary.stainburn@ringways.co.uk>
To: pgsql-sql@postgresql.org
Subject: unique keys / foreign keys on two tables
Date: Thu, 29 Nov 2012 10:14:27 +0000
Message-ID: <201211291014.27989.gary.stainburn@ringways.co.uk> (raw)
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-sql>
I'm designing the schema to store a config from our switchboards.
As with all PBX's the key is the dialed number which is either an extension
number or a group (hunt/ring/pickup) number.
I have two tables, one for extensions and one for groups, basically
ext_id int4 primary key
ext_desc text
....
....
....
and
grp_id int4 primary key
grp_desc text
.....
.....
.....
I now need to be able to ensure the id field is unique across both tables.
Presumably I can do this with a function and a constraint for each table.
Does anyone have examples of this?
Next I have other tables that refer to *destinations* which will be an ID that
could be either an extension or a group. Examples are 'Direct Dial In'
numbers which could point to either. How would I do that?
--
Gary Stainburn
Group I.T. Manager
Ringways Garages
http://www.ringways.co.uk
--
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To: pgsql-sql@postgresql.org
Cc: gary.stainburn@ringways.co.uk
Subject: Re: unique keys / foreign keys on two tables
In-Reply-To: <201211291014.27989.gary.stainburn@ringways.co.uk>
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