Message-ID: <4AAE5141.70300@megafon.hr>
Date: Mon, 14 Sep 2009 16:20:49 +0200
From: Mario Splivalo <mario.splivalo@megafon.hr>
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To: Tom Lane <tgl@sss.pgh.pa.us>
CC: pgsql-sql@postgresql.org
Subject: Re: CHECK constraint on multiple tables
References: <4AAE43F8.4000107@megafon.hr> <15921.1252937895@sss.pgh.pa.us>
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Tom Lane wrote:
> Mario Splivalo <mario.splivalo@megafon.hr> writes:
>> I have two tables, tableA and tableB:
>> CREATE TABLE tableA (idA integer primary key, email character varying
>> unique);
>> CREATE TABLE tableB (idB integer primary key, email character varying
>> unique);
> 
>> Now, I want to create check constraint in both tables that would
>> disallow records to either table where email is 'mentioned' in other table.
> 
> Have you considered refactoring so there's only one table?

Unfortunately I can't do that, due to the
object-relational-mapper-wrapper-mambo-jumbo.

The only 'logical' idea that I can think of is separating emails to the
third table, and then use UNIQUE constraint on the email field on that
table, and then use FK constraint so that email fields in tables tableA
and tableB points to the email in the table emails.

	Mario