Re: One-To-One Relationships

From: David Cressey <>
Date: Fri, 30 Nov 2007 18:38:39 GMT
Message-ID: <PMY3j.9$QS.1_at_trndny03>

"Tegiri Nenashi" <> wrote in message
> On Nov 30, 8:19 am, Jan Hidders <> wrote:
> The distinction between entities /
> > relationships, domain objects / predicates is pretty well-established
> > in linguistics, philosophy and logic.
> That certainly means you can define them formally in database terms,
> right?
> Here is one such attempt:
> It defines an entity as a relation (aka table:-) with a single
> noncomposite key, and relationship as a table with composite key. Does
> this definition pretty much exhausts the entity-relationship theory?

Not good. An entity is not a relation. The data stored in a relation describes an entity or a relationship among entities. The difference between "is" and "describes" is important. Received on Fri Nov 30 2007 - 19:38:39 CET

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