- From: Uche Ogbuji <uche.ogbuji@fourthought.com>
- Date: Tue, 28 Sep 2004 10:39:54 -0600
- To: "Seaborne, Andy" <andy.seaborne@hp.com>
- Cc: Alessandro Di Bella <aldib@fuurou.org>, www-rdf-interest@w3.org
On Wed, 2004-09-08 at 04:55, Seaborne, Andy wrote: > Query expressions in RDQL are of fixed length so, no, you can't write an > arbitrary reachability query. > > One way it can happen is if the source provides inference and there is > some super property which is transitive. Then it is just a matter of > asking (?x :p ?y). > > An example would be rdfs:subClassOf. Note: this is easy to express in Versa[1] without any special arrangement in the data model traverse(tn1, all(), vtrav:transitive) > Do you have a concrete use case for this requirement? The RDF Data > Access Working group is working on a query language and it is gathering > requirements: > > http://www.w3.org/TR/rdf-dawg-uc/ One of many example use cases: my app is about to delete a node and wants to do simple processing on each connected node. I'd use such a query to get a list of resources my app can then simply iterate over. [1] http://uche.ogbuji.net/tech/rdf/versa/ -- Uche Ogbuji Fourthought, Inc. http://uche.ogbuji.net http://4Suite.org http://fourthought.com A hands-on introduction to ISO Schematron - http://www-106.ibm.com/developerworks/edu/x-dw-xschematron-i.html Wrestling HTML (using Python) - http://www.xml.com/pub/a/2004/09/08/pyxml.html XML circles the globe - http://www.javareport.com/article.asp?id=9797 Principles of XML design: Considering container elements - http://www-106.ibm.com/developerworks/xml/library/x-contain.html Hacking XML Hacks - http://www-106.ibm.com/developerworks/xml/library/x-think26.html A survey of XML standards - http://www-106.ibm.com/developerworks/xml/library/x-stand4/
Received on Tuesday, 28 September 2004 16:40:28 UTC