- From: Peter Breton <pbreton@MIT.EDU>
- Date: Tue, 12 Jun 2001 09:23:18 -0400
- To: www-rdf-dspace@w3.org
[These are some comments on an automatic RDF generation mechanism that I've been working on for DSpace. Mick and I thought these ideas might be of wider interest. The generation demo is here: http://www.dspace.org/dspace-demo/test/testrdf.jsp To see the RDF without HTML quoting, use: http://www.dspace.org/dspace-demo/test/testrdf.jsp?noquote=true ] Now that I've done this first bit (which is built on Jena), I have all sorts of questions/problems/issues: * The automatic generation really doesn't address the idea of object identity. The identifiers you see in the demo, like http://www.dspace.org/org.dspace.db.generated.Publication/1094533159 just use the object's hash code, which is transient. I think a Publication wants to be mapped to its persistent id (perhaps its handle), but this is outside the Bean spec, which really only addresses in-memory objects. * The generated RDF only captures the field values at a particular moment. What happens when we capture an RDF dump of a publication at Submit time, and another one when it is modified? There are also some more mundane features that would be nice: * There should be some custom field mapping, which says which fields are ignored, and provides alternate labels for arcs. * The various Java collection objects (Object[], Hashtable, Vector, Enumeration in JDK 1.1; Collections and Iterators in JDK 1.2 and up) should be automatically recursively processed. * When the value of a property is itself an Object, that object should (probably) be recursively processed. And for future directions, thoughts about the implications of SQL-based persistence and RDF querying are welcome. One possible direction I see for RDF querying (I'm not sure if it has been thought of already) is to provide a query capability which uses XML Schema. So, if a Literal value had type xsd:string, then operators like 'starts_with', 'contains', and the like could be applied to it. These operations could be mapped back to the native facilities of the storage component (in this case, SQL operations like 'foo%', '%foo%', and so forth). Peter
Received on Tuesday, 12 June 2001 09:23:54 UTC