Subject: Re: ebXML Representation of Metadata
At 08:22 AM 5/26/00 +0100, Martin Bryan wrote: > > At this point it might be interesting to note, > > that RDF is perfectly capable of transporting > > UML data, since UML is just a specific > > RDF vocabulary. Please note that RDF is > > also capable of encoding instance data based > > on specific UML vocabulary - eg. RDF represents > > not just a class person, but also a specific person > > "Stefan". > >Being based on a simple tuple model RDF is capable of describing anything. >The question is whether or not it is capable of describing anything >efficiently in a manner that allows that data to be a) queried in human >understandable terms (i.e. not using RDF terminology) and b) maintained >in distributed databases (i.e. can I extract parts the different parts of >an RDF stream so that they can be used to update different databases >efficientily). You are right. Lets compare the two approaches: To query an RDF-Model for all defined UML-Classes one just asks for all instances of UML:Class, which returns another RDF-Model. An example query with a suitable API (eg. http://WWW-DB.Stanford.EDU/~melnik/rdf/api.html ) would look like: RDFModel allClasses = myUMLDoc.find("rdf:type","UML:Class"). How would one query an XMI-Document? Using a SAX-Parser and looking at the events? Examining the DOM Model of the Document? This is obviously the wrong level of abstraction. So one has to recreate most of the RDF-Datamodel for XMI to be able to pose queries. But that means (since RDF has the simplest possible structured datamodel) the XMI-UML-model will be translatable to RDF very easy (or to put in another way: then XMI is just a special RDF syntax - which is fine). Best, Stefan >Martin Bryan
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