xml-dev - re: Soft Landing

[David Megginson <david@megginson.com>]

Dave Winer writes:

 > I wonder if anyone is interested in trying to set up a
 > mini-Semantic Web of content describing the people on this list,
 > what their interests are, what software they use, who else they
 > know, etc. My poor little mind needs to try something pragmatic to
 > figure out what all this stuff means. Dave

Step one -- whether you're using RDF, Topic Maps, SOAP's serialization
format, or XMI, is to decide what your classes are and what your
properties are (note that I didn't say the classes and *their*
properties).  One of the classes is easy enough:

- Person (or to include orgs, etc., Party)

But what after that?  Should we have an Interest class to represent
shared interests, a WebSite class to represent Web sites, etc., or
should we represent them simply as text strings?  Here's the
difference, first with just text strings (denormalized):

  <xd:Person rdf:about="http://megginson.com/ids/p001">
   <xd:name>Dave Winer</xd:name>
   <xd:interest>XML</xd:interest>
   <xd:mailing-list>xml-dev</xd:mailing-list>
  </xd:Person>

  <xd:Person rdf:about="http://megginson.com/ids/p002">
   <xd:name>David Megginson</xd:name>
   <xd:interest>XML</xd:interest>
   <xd:mailing-list>xml-dev</xd:mailing-list>
  </xd:Person>

and then with more classes and objects (normalized):

  <xd:Person rdf:about="http://megginson.com/ids/p001">
   <xd:name>Dave Winer</xd:name>
   <xd:interest rdf:resource="http://megginson.com/ids/i001"/>
   <xd:mailing-list rdf:resource="http://megginson.com/ids/m001"/>
  </xd:Person>

  <xd:Person rdf:about="http://megginson.com/ids/p002">
   <xd:name>David Megginson</xd:name>
   <xd:interest rdf:resource="http://megginson.com/ids/i001"/>
   <xd:mailing-list rdf:resource="http://megginson.com/ids/m001"/>
  </xd:Person>

  <xd:Interest rdf:about="http://megginson.com/ids/i001">
   <xd:name>XML</xd:name>
  </xd:Interest>

  <xd:MailingList rdf:about="http://megginson.com/ids/m001">
   <xd:name>xml-dev</xd:name>
  </xd:MailingList>

The second one is obviously more flexible, but at the cost of
increased complexity -- in a real-world model, this would explode into
hundreds or thousands of objects for only a few people and their
interests.

Anyway, this is an example of the kinds of decisions people need to
make with or without a semantic web -- the design problem is where
implementors spend most of their time and money, and RDF or XMI or
Topic Maps or SOAP don't make that part any simpler.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/