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Re: plural vs singular properties (a proposal)

From: Garret Wilson <garret@globalmentor.com>
Date: Fri, 04 Jan 2008 19:15:02 -0800
Message-ID: <477EF636.6000703@globalmentor.com>
To: Sampo Syreeni <decoy@iki.fi>
CC: Bruce D'Arcus <bdarcus@gmail.com>, Sandro Hawke <sandro@w3.org>, semantic-web@w3.org


Sampo Syreeni wrote:
> On 2007-10-18, Garret Wilson wrote:
>> [...] A more thoughtful merging would simply advance the order values 
>> of one of the sets so that the properties remain with the same 
>> relative order, but simply one ordered property set comes after the 
>> other. [...]
> I think a more serious problem is that you are using ordering as a 
> vehicle for carrying many different kinds of semantics. For example, 
> under an RDBMS, you'd be forced to model whatever the order carries 
> using new columns, with an explicit domain, a name, clear definitions, 
> constraints and normalization. This happens because only unordered 
> sets are available for modeling, and it's an explicit design feature 
> of the relational model.

I'm still keeping your comments in mind. I've been doing some more 
serious study of the relational model, and your comment regarding "only 
unordered sets" raises another question. Does the presence of repeated 
properties in general in RDF cause you similar concerns? After all, RDF 
differs from the relational model here by allowing repeated predicates, 
which breaks the "only unordered sets pattern."

I ask this seriously, not rhetorically. After reading sufficient C.J. 
Date as he rails against SQL's duplicate rows and NULLs, I've become 
slightly uncomfortable with the idea of duplicate predicates in general, 
both in RDF and URF. How does RDF justify repeated properties?

Received on Saturday, 5 January 2008 03:16:45 UTC

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