|
[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Why not RDF rather than RSS for the Web of Data? -was Some
Michael Champion wrote: > On 4/25/05, Bill de hÓra <bill.dehora@p...> wrote: > >>. However you could replace the >>Atom above with RDF1.0 and let the entire feed pass straight through to >>the RDF aware layer - nothing would break. This kind of flexibility is >>worth keeping in mind the next time someone here dings RDF because it >>can't describe Fahrenheit to Celsius conversions. It ain't pretty, but >>it does have interesting properties, Turing completeness not being among >>them. > > > I don't doubt that RDF logically could meet the use cases Bosworth was > talking about, nor do I doubt that XQuery views of diverse data > sources logically could meet those requirements. The question is > whether they have those "S" attributes (simplicity, sloppiness, > standardization, scalability) he asserts are necessary to thrive on > the Web. Oh sure, he's said before (more or less) that RDF doesn't have the characteristics needed for web adoption. That's the world where XML well-formedness is a nice to have. On the other hand, compared to the kind of work that goes in relational database designs for enterprises, RDF graphs counts as slop - I'll try to demonstrate that here. > I don't really care which "wins" -- something RSS-like or something > RDF-like -- to become the data format for the Web of Data (if such a > thing ever exists). Both are at XML-ish. I believe Bosworth's > analysis enough to bet on RSS, if I had to make a prediction: > - It has proved simpler to actually use by ordinary mortals > - The RSS culture and toolset is tolerant of error, ambiguity, and > other human characteristics > - RSS people can't agree on a formal standard but it is ubiquitous and > interoperable in practice > - Its growth curve indicates that it scales to the Web and leverages > HTTP nicely. > > I don't think any of these can be said about RDF. Simplicity (for > users), sloppiness (tolerance of error), and standardization (in the > sense of ubiquity) are just not among RDF's virtues. I don't know > about scalability one way or the other, and its relationship with HTTP > seems a bit rocky. That depends. Simplicity, sure, but not tolerance of error. RDF-aware systems are highly tolerant of absent or unexpected data; arguably they go too far in that respect - it becomes a bit of free for all. To highlight this, let's look at the stuff that gets pulled out of the Atom example I sent earlier, and sent to said 'RDF layer': <rdf:RDF xmlns:iam="http://www.reach.ie/iams/envelope/" xmlns:event="http://www.reach.ie/iams/event/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <event:Event> <event:EventSourceTime/> <event:EventSource rdf:resource=""/> <event:EventLevel rdf:resource=""/> <event:EventDescription/> <event:EventObject rdf:resource="" rdf:type=""/> </event:Event> <rdf:Description rdf:about=""> <iam:Version/> <iam:MessageType rdf:resource=""/> <iam:MessageRole rdf:resource=""/> <iam:MessageSource rdf:resource=""/> <iam:EnvelopeType rdf:resource=""/> <iam:MessageSourceID/> <iam:MessageDestination rdf:resource=""/> <iam:CorrelationID rdf:resource=""/> <iam:MessageID rdf:resource=""/> <iam:SequenceNo/> </rdf:Description> </rdf:RDF> It's a much less prim technology that people suggest. The following scenarios will work: - send just one of those, - a thousand of those. - just the event:* stuff - just the iam:* stuff - part of the event:* data - part of the iam:* data - new iam:* stuff - new event:* stuff - dc:* stuff in either event:* or iams:* or both. - *:* stuff in either event:* or iams:* or both. - a FOAF block, every now and then - RSS1.0 outside the RDF, you can send the lot right through - logging a software upgrade: <rdf:RDF xmlns:event="http://www.reach.ie/iams/event/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:doap="http://usefulinc.com/ns/doap#"> <event:Event> <event:EventSourceTime/> <event:EventSource rdf:resource=""/> <event:EventLevel rdf:resource=""/> <event:EventDescription/> <event:EventObject rdf:resource="urn:XXX" rdf:type=""/> </event:Event> <doap:Project rdf:about="urn:XXX" rdf:type="urn:hmm...upgrades"> <doap:release> <doap:Version> <doap:name>agent.jar</doap:name> <doap:revision>1.1.1</doap:revision> </doap:Version> </doap:release> </doap:Project> </rdf:RDF> No surprise then to find RDF diehards looking at mU/mI processing models, concepts like 'foreign markup', or non-optional typing, @rel, and shaking their heads. cheers Bill
|
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
|
|||||||||






