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Re: unhappy responses

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Mon, 9 Mar 2009 15:26:58 -0400
Message-ID: <29af5e2d0903091226jdd48639n50b81efe82a480b7@mail.gmail.com>
To: W3C OWL Working Group <public-owl-wg@w3.org>
I've followed up with Marijke about the issue of hasKey. The issue for
her is that "key" has a specific meaning in the ER and Conceptual data
modeling worlds and that the common notion is that keys are
functional. Because of the overlap of our user base with that one, she
suggests at least a short note in syntax commenting on the difference
between our keys and what people will be familiar with, and suggests
that one of our user facing documents show how to map keys in this
other sense to our keys (i.e. hasKey + functional properties).

In support of her view she offers two citations:

"The Entity-Relationship Model-Toward a Unified View of Data",by Peter
Pin-Shan Chen, that she considers a foundational paper in the area,
which says, among other things: "Basically, an entity key is a group
of attributes such that the mapping from the entity set to the
corresponding group of value sets is one-to-one."

This paper is available at

"Information Modeling and Relational Databases", ed. 2008, By Terry
Halpin, Tony Morgan, from which she points at, among other places,
figure 5.16 and the description on page 174-175.

This book is on google books and the following link should bring you
to the figure in question: http://tinyurl.com/d8gshx

Received on Monday, 9 March 2009 19:27:39 UTC

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