Begin forwarded message:
> From: Jonathan Borden <>
> Date: June 9, 2004 8:41:34 PM EDT
> To: "Dare Obasanjo" <>
> Subject: Re: [xml-dev] Meta-somethingorother (was the semantic web
> mega-permathread thing)
>
> Dare Obasanjo wrote:
>
>>> -----Original Message-----
>>> From: Bill de hÓra [mailto:]
>>> Sent: Wednesday, June 09, 2004 2:58 PM
>>> To: XML Developers List
>>> Subject: Re: [xml-dev] Meta-somethingorother (was the
>>> semantic web mega-permathread thing)
>>>
>>>
>>> I suggest making an informed decison - read the RDF or OWL
>>> Model Theory and decide for yourself whether
>>> XML+Namespaces+HTTP cover it off - if you come back and say
>>> yes, then we'll have something to talk about.
>>
>> I've read a little RDF & OWL model theory and have failed to see what
>> they buy me above and beyond basing my applications on
>> XML/XPath/XSLT/XSD/XQuery. RDF people like pretending that the XML
>> family of technologies ends with the XML 1.0 spec when this is far
>> from the truth.
>
> One difference, but clearly not the only difference, is that the OWL
> DL subset allows you to use description logic inferencing engines with
> "knowledge bases" (i.e. a collection of triples) that conforms to OWL
> DL. Perhaps this doesn't float your boat, but this is *one* example of
> something that you can do using OWL that XML/XPath/XSLT/XSD/XQuery
> doesn't allow you to *directly* do. The reason that I say *directly*
> is that one can also quite easily come up with an XML format that is
> OWL DL compatible (e.g. the OWL *XML* presentation syntax).
>
> I suppose for fun you might write a DL inferencing engine in XSLT.
> Perhaps that could be a new test that Microsoft can give interviewees
> :-)
>
>>
>> I also find it interesting that almost every RDF booster talks about
>> how the benefit of RDF is that you can dump all this wonderful
>> semantic data in an RDF store and then query it.
>
> yawn.
>
>> So where exactly are these RDF stores or standard RDF query
>> languages? I can dump XML data into a relational database today and
>> query it with SQL. I even could dump it in an XML database [or
>> relational database with an XML datatype] and query it with XQuery or
>> XPath.
>>
>> What exactly do RDF technologies buy me over using XML technologies
>> for doing queries over FOAF + RSS 1.0 data, for instance.
>
> Nothing in that instance. For less trivial examples you can do quite
> alot in SQL (or XQuery, or even XSLT) with the use of procedures.
>
> The particular value of OWL/RDF is that the model theory licenses a
> well defined set of inferences given any particular set of triples in
> the same fashion that SQL defines a set of result tuples based on a
> set of tables and a given SQL statement.
>
> OWL is great for expressing classifications of things where one is not
> concerned about whether the "thing" is an attribute or element (in
> that specific case one can use XSD for example) but where things might
> be taxonomies of birds, or bacteria or chemotherapy agents, or genes
> or chemicals or diseases or books or ... anything that you might want
> to classify. When you make assertions about categories the "system"
> understand that you are making such assertions about each instance of
> each of the category's subcategories.
>
> If you aren't that interested in classifying things, then OWL probably
> isn't that useful to you. (Either that, or you haven't learned about
> the cool things that you can do when things are classified (assuming
> that you consider doing stuff like medical diagnosis cool)).
>
>>
>> PS: Then there's the fact that RDF doesn't deal that well with mixed
>> content.
>
> There is this fact.
>
> Jonathan
>
