W3C home > Mailing lists > Public > www-rdf-interest@w3.org > November 2004

Re: I guess it's a stupid questions...

From: Daniel O'Connor <daniel.oconnor@gmail.com>
Date: Sat, 13 Nov 2004 19:54:38 +1030
Message-ID: <106cc12004111301244b88b863@mail.gmail.com>
To: www-rdf-interest@w3.org

Perhaps this needs a more of a hands on demonstration.

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
</box>

XML. Fine and dandy. We know what a "box" is and what it's height,
width and depth properties are. You add in an extra property, and you
either have to change the schema or start using namespaces.

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains>Fish</contains>
</box>

Okay, nothing too hard about that. Let's give the fish a name.

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains><fish name="bob" /></contains>
</box>

That's wonderful. What if we want to take bob the fish out of our box?


<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains nodeID="bob"></contains>
</box>

<fish nodeID="bob" name="bob" />

Now, let's give bob a homepage.

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains nodeID="bob"></contains>
</box>

<fish nodeID="bob">
<name>bob</name>
<homepage>http://www.fish.com/</homepage>
</fish>

What if there's too much information about bob the fish to express
every time you want to talk about bob? Let's take the definition of
bob the fish and put him in an xml file on his homepage.

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains nodeID="bob"></contains>
</box>

<fish nodeID="bob">
<seeAlso>http://www.fish.com/bob.xml</seeAlso>
</fish>

Now, what if we didn't even know Bob was a fish, he was just a strange
mystery object in a box?

<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains resource="http://www.fish.com/bob.xml" />
</box>

And, if we want to say that bob is a fish, we know his name but we
don't know much else - his homepage has more information though.


<box>
<width>1</width>
<height>1</height>
<depth>1</depth>
<contains resource="http://www.fish.com/bob.xml" />
</box>

<fish about="http://www.fish.com/bob.xml">
<name>bob</name>
</fish>

Suddenly, we've a lot of things that could go in the box. We don't
need to know about them, we just need to know where we *can* find out
more about them. Say we only know that bob is a fish in a box, not
what type of fish. We can use a common definition of a Fish (from
something like WordNet) and point to bob's description - which would
then offer a more meaningful description of Bob, the Flying Fish.

This is was RDF, RDFS and OWL are all about. Things getting more
detailed the more you look into them. XML can't really provide
*meaning*, which RDF can.

Does that clarify anything, or does it all seem a little fishy?

-Daniel O'Connor

-- 
http://www.ahsonline.com.au/dod/FOAF.rdf
Received on Saturday, 13 November 2004 09:24:40 UTC

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