Re: Strawman DAML+OIL Query Language Proposal

From: Dan Brickley (
Date: 08/28/01


I like this. It is (unless I'm mistaken) basically the same as the
language broad-brush sketched in the W3C QL'98 position paper "Enabling
Inference", (and implemented in
Guha's RDFdb and Libby Miller's Inkling system as 'Squish'). It don't say
this to complain, but rather to note that it's pretty much the simplest
useful query language for RDF/D+O that's still useful. There are many
other things one might want from an RDF query language, but there's also
much to be gained from picking a simple simple subset to encourage
implementors to ship code early. IMHO something like Squish fits the bill

It's also the same idea expressed in a recent joke from Pat Hayes, that
we could have a "Query Description Framework" through defining a format
that pairs an RDF graph with, "".

One claim from that might
bear some discussion:

RDF Schema constructs such as subClassOf and subPropertyOf
allow some simple inferences. In future, more complex rules will be
expressible and more powerful inference engines will become possible.
Ideally, the query language used by an inferencing system to access
the knowledge base should be the same the query language the inferencing
system responds to.

To enable this, a query can take an additional parameter which specifies
whether its answer should be based on either the  "raw RDF graph" or on
the deductive closure of the knowledge base.


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