[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RDF not conforming to the Namespace spec?
Hi Folks, There has been a lot of discussion on this list group about namespaces and how there is no necessary link between a namespace URI and a schema (DTD). Just as I was accepting that and getting comfortable with it I read the RDF spec... For those of you unfamiliar with RDF, its mission in life is to enable you to express data about your data; i.e., metadata. You can express things like, "the creator of the BookCatalog is John Doe". "creator" is a piece of metadata about the "resource", BookCatalog. In RDF "creator" is called a "property". Thus, the "property" <creator> has the "value" John Doe ... <creator>John Doe</creator>. Okay, here's where the rub comes. Let me give you a couple of quotes from the RDF spec (the *'s I have put in and are my way of emphasizing the words that I wish for you to really focus on): "Property names *must* be associated with a schema. This can be done by qualifying the element names with a namespace prefix to unambigously *connect* the property definition with the corresponding RDF schema ..." Earlier in the spec it says: "Due to RDF's incremental extensibility, agents processing metadata will be able to trace the origins of schemata they are unfamiliar with back to known schemata and perform meaningful actions on metadata they weren't originally designed to process." Let me tell you how I interpret those two sentences. Suppose that I haver written a Web agent and it comes across a Web site that serves up an XML document containing some metadata (expressed using the RDF syntax). Let's suppose that the metadata says, in XMLese, "the creator of the BookCatalog is John Doe". My agent has never seen the property "creator", so it follows the namespace URI to the property schema. From there it finds the superclass of the creator property. If it doesn't recognize that class then it goes to its superclass. It keeps doing this until it finds a class that it understands and then it starts unwinding (presumably by this process it will be able to gain insight into what "creator" is all about. I have no idea how this will happen, but it sounds pretty cool.) This mechanism of following references until the agent gains "enlightenment" makes sense to me. I like it! ***However*** that presupposes that there is a *guaranteed* association between a namespace URI and a schema. This is totally against what this list group has worked so hard to clarify as NOT being the case. Somebody help me to understand this. Obviously I am misreading, misinterpreting the RDF spec. Thanks. /Roger xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|