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Re: PRIMER: draft data model section

From: Frank Manola <fmanola@mitre.org>
Date: Mon, 15 Oct 2001 07:54:20 -0400
Message-ID: <3BCACE6C.802@mitre.org>
To: Aaron Swartz <aswartz@upclink.com>
CC: w3c-rdfcore-wg@w3.org

Thanks for the comments.  I think you've put your finger on some key 
decisions we need to make about how to present this material (which I 
think needs some discussion), since most of the points you've identified 
involve deliberate choices.  Detailed remarks below:

Aaron Swartz wrote:

> Nice work on this piece, some comments:
> On Sunday, October 14, 2001, at 06:47  PM, Frank Manola wrote:
>> “the creator of [the particular Web page we’re talking about] is “John 
>> Smith” “
> You seem to imply that the character string "John Smith" wrote this web 
> page. As DanC pointed out: "I don't think a 10 character string created 
> a web page."

I don't either, but at this point, I'm trying to express things the way 
I think people might normally think about expressing them.  I try 
(possibly a little indirectly) later on to clarify this point, but I'm 
not sure it's the right thing to start off addressing the name vs. 
resource issue right away (although it could be more clearly identified 
as an issue further along, I suspect).  This is certainly one of the 
presentation decisions that needs to be made though.

BTW:  Regarding both this issue, the other issues you raise below, and 
any others that come up, I don't necessarily feel strongly about these 
things;  I'll be happy to rewrite the text to present the material in 
whatever order the WG feels is most appropriate.  Just keep in mind that 
there are going to be some folks who start off from a primarily Web 
background, and to whom metadata and descriptions are the new concepts, 
while there are going to be other folks who start off from a database, 
metadata background, and to whom Web concepts are the new things (and 
probably other groups as well).  We need to make sure we're talking 
clearly to everyone.

> Also, you continually use "the" in your RDF statement examples. Since 
> little-to-nothing is definitive on the Semantic Web, perhaps "a" would 
> be more appropriate as in, "John Smith is a creator of 
> http://www.foobar.org/index.html".

It's true that nothing is definitive on the Semantic Web, but once again 
I wonder whether it's appropriate to get into that right away.  In this 
case, what the writer of the RDF probably *wants* to say is actually 
"the" (whether the writer is actually able to *mean* that in RDF, given 
your point, is another matter).  This is another presentation decision.

>>     the predicate is the characteristic identified by “creator”
> As the term predicate seems to confuse a lot of people, perhaps "verb" 
> or "property" might be better.

I'd prefer "property" (or "attribute") myself, but one of the things I'm 
doing here is introducing the *RDF* terminology, which seems to 
"officially" be "predicate".  We could always change that.

>> The triples representing the above three statements would be written:
>> http://www.foobar.org/index.html   “creator”           “John Smith”
> Can we use a URI for a property, since literal properties aren't allowed 
> in RDF 1.0. Even better, can we use N-Triples syntax for these 
> statements. You correct this later, but I think it'd be better to keep 
> things correct from the beginning.

This was another deliberately-made decision.  I've seen several 
presentations (including yours) that use URIs for properties (and other 
things) from the beginning.  This means introducing URIs at the 
beginning (which you do).  That certainly is one way to approach the 
problem, but I thought I'd try it this way.  I admit that the transition 
from strings to URIs creates a difficulty (which I try to address 
explicitly), but it seemed to me that, from the data modelling point of 
view, attribute-value pairs (with string names for the attributes) are 
very natural, and URIs are an extension, and I wanted to convey "the 
general idea" first, and reinforce its relationship to this common data 
modeling approach.  This is yet another presentation decision.  (I 
suppose I could also further clarify that what's being presented in this 
initial section is "not quite RDF", but that wouldn't address your basic 

> You might also want to replace foobar.org with example.org.

Good idea.

> -- 
> [ "Aaron Swartz" ; <mailto:me@aaronsw.com> ; <http://www.aaronsw.com/> ]

Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
Received on Monday, 15 October 2001 07:53:45 UTC

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