- From: Janne Saarela <janne.saarela@profium.com>
- Date: Fri, 02 Apr 2004 10:49:00 +0300
- To: public-rdf-dawg@w3.org
- Cc: Patrick Stickler <patrick.stickler@nokia.com>
Following yesterday's teleconference I would like to continue discussion on this support for arbitrary datatypes in a query. I suggested that if the support is really for any arbitrary datatype, for a DAWG recommendation compatible RDF query processor we need to lay a set of minimal datatypes it needs to support. This would enable us to lay a minimal set of operators that operate on these datatypes. I suggest the minimal set of datatypes would be a subset of all XML Schema datatypes. I leave it up to further discussion to see which ones are truly necessary. Janne > 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 > > > -- Janne Saarela <janne.saarela at profium.com> Profium, Lars Sonckin kaari 12, 02600 Espoo, Finland
Received on Friday, 2 April 2004 02:49:40 UTC