A Query Language Based on DAML

Here is yet another RDF query language. This one has a simple framework but
can handle very general queries by incorporating DAML class expressions.

This proposed design arose out of a need for a query language that could be
expressed in RDF and be implemented over various simple, conventional (i.e.
non-RDF) data sources.  But DAML lets it scale up to a fairly general query
language.

A query is expressed in RDF.  It looks like this:

 <Query>
  <select rdf:resource="property1"/>
  <select rdf:resource="property2"/>
  ...
  <from>
   <daml:Class>
    <!-- body of a DAML class expression -->
   </daml:Class>
  </from>
 </Query>

Several queries and class expressions are combined into a composite request
like this:

 <Request>
  <declare>
   <daml:Class ID="class-expr1">
    <!-- body of a DAML class expression -->
   </daml:Class>
  </declare>
  ...
  <evaluate>
   <Query>
    <!-- body of a Query, may reference above class-expr's -->
   </Query>
  </evaluate>
  ...
 </Request>

The full details are here: http://www.langdale.com.au/RDF/DAML-Query.html
and a DAML Ontology for it is here:
http://www.langdale.com.au/RDF/daml-query.rdf .

Its not implemented yet, so comments would be nice to hear even if they say
"this has already been done".

Cheers,
Arnold

--
Arnold deVos
Langdale Consultants
adv@langdale.com.au

Received on Saturday, 16 February 2002 01:49:17 UTC