PS-8: Query with Datatype Value Comparison & Support for Arbitrary Datatypes in Query

A client wishes to discover all resources which are of rdf:type
ex:Person, and have an ex:ageInYears which is between "16"^^ex:count
and "18"^^ex:count, inclusive.

The client is aware of a knowledge source from which such
resources might be discovered.

Following the DAWG recommendation, the client formulates a query
which expresses the desired characteristics to match and submits
the query to the knowledge source.

The knowledge source returns zero or more resource descriptions
describing the matched resources.

--

I deliberately used unknown datatypes in this example to illustrate
the need to be able to allow arbitrary datatypes in input queries,
regardless of what datatypes a particular query resolution engine
may be able to handle.

Note that if the client is able to include auxiliary knowledge
which may be relevant to resolution of the query along with
the query itself (e.g. in a single input RDF graph) this would allow
the client to provide information about the terminology used
in the query, such as about the nature of particular datatypes,
their relationship to other datatypes, and even references to
formal definitions of the datatypes which could be used by the
knowledge source to evaluate typed literals and perform comparisons.
E.g. the auxiliary knowledge could indicate an XML Schema which
defines the datatype in question, and if the knowledge source is
able to understand XML Schemas, could load and utilize to deal
with values of that datatype.

--

Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com

Received on Thursday, 18 March 2004 02:18:25 UTC