Short Essay: Squeezing RDF into a Java Object Model

[Tim Bray]

At 11:21 AM 5/3/99 -0400, David Megginson wrote:
>The more I work with RDF, the more I find it fascinating in the
>abstract but annoying in the concrete.

Hmm, as I write this, I'm chewing away on a data set with about
half a million RDF tuples.  I'm having an easier time of it than
David, but I think that's because I'm trying to do less.  Mostly,
my software needs to answer two questions:

(a) what are all the properties of URL XXX?
    variation: what is the value (if any) of URL XXX's property YYY?
(b) what URLs have <boolean-combination-of-property-names-&-values>?

There are two bits of complexity - one is that you have a boolean
associated with each property value saying whether it's a literal
or a URL.  Although I haven't actually used it - in my data set, 
some properties always have literal values, others always have
URL values.

The second is the "aboutPrefix" stuff, which on reflection I consider
a hideous bogosity.  I know how it got into RDF, they had a drop-dead
requirement to be able to emulate PICS, which has this prefix stuff.
I can even understand how you might use it, but I still think it's
a mistake.  It doesn't get in the way of question (a) above, but it 
certainly plays hell with (b).

Perhaps the key is that I'm not trying to construct a comprehensive
object model - I'm just trying to use metadata to look things up.
I find RDF just fine for that.  -Tim

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