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Message-ID: <42E7E9B3.4080500@endpoint.com>
Date: Wed, 27 Jul 2005 16:08:19 -0400
From: Jeff Boes <jeff@endpoint.com>
Organization: End Point
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To: pgsql-sql@postgresql.org
Subject: Foreign key with check?
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Given a table like this:

create table primary (
  a integer primary key,
  b boolean
);

And another like this:

create table secondary (
  a integer,
  some_other_fields
);


I would like a foreign key constraint on the "secondary" table that
looks something like:

foreign key (a, true) references primary (a, b)

That is, a row in "secondary" is allowed to reference a row in "primary"
if and only if that referenced row has (b = true).

I think I have to do this with an additional trigger. Any other options?