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Re: Klyne Contexts: 3. Statements sets in RDF

From: David Megginson <david@megginson.com>
Date: Sat, 30 Dec 2000 07:33:55 -0500 (EST)
Message-ID: <14925.54835.622404.630657@megginson.com>
To: "RDF interest group" <www-rdf-interest@w3.org>
Bill de hÓra writes:

 > Jonas is right but not only for that reason. The RDF numeral
 > identifier scheme doesn't come with the everyday semantics people
 > associate with numbers, specifically numeric ordering. They are
 > just tokens that happen to be confusing to the human reader. Seq
 > does require ordering though. I like to see this sceheme dropped,
 > it seems to bend the readability req of XML (it's very readable but
 > very confusing), but what would replace it?

There are two alternatives:

1. revise the spec to declare that RDF statements are ordered to begin
   with (i.e. a processor that reads an RDF document preserves the
   relative order of all statements for any given resource); or

2. use resources for property values and add positional information, i.e.

  <foo:Person rdf:about="urn:xxx:0001">
   <dc:title>Joe Smith</dc:title>
   <foo:job-history rdf:parseType="Resource">
    <foo:job-item dc:title="Intern" foo:pos="1"/>
    <foo:job-item dc:title="Sales Rep" foo:pos="2"/>
    <foo:job-item dc:title="Sales Regional Manager" foo:pos="3"/>
    <foo:job-item dc:title="Booth Babe" foo:pos="4"/>
    <foo:job-item dc:title="VP Sales" foo:pos="5"/>
   </foo:job-history>
  </foo:Person>

(I wrote the above example in heavily-abbreviated RDF syntax, and will
leave it as an exercise for the masochistic reader to write it out in
fully unabbreviated RDF syntax.)

The problem with #1 comes when you read information from more than one
RDF document, and the relative ordering becomes non-obvious.  I agree,
by the way, that Seq, Alt, and Bag are FUBAR.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/
Received on Saturday, 30 December 2000 11:55:01 GMT

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