Re: Relationship Question
From: David Portas <REMOVE_BEFORE_REPLYING_dportas_at_acm.org>
Date: 14 Oct 2006 16:08:09 -0700
Message-ID: <1160867289.795323.238290_at_i42g2000cwa.googlegroups.com>
Date: 14 Oct 2006 16:08:09 -0700
Message-ID: <1160867289.795323.238290_at_i42g2000cwa.googlegroups.com>
Logan wrote:
> Is the following a true and accurate statement within the context of a
> physical schema?
>
> "a foreign key constraint defines a relationship to another table"
>
> Thanks,
> Logan
It would be more accurate to say "enforces" rather than "defines". Relationships are represented by values within tuples within relations. A foreign key constraint is just one type of constraint (not the only one) for guaranteeing the integrity of certain binary relationships.
A foreign key is part of the logical model rather than the physical one.
-- David PortasReceived on Sun Oct 15 2006 - 01:08:09 CEST