Cart
|
[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: an unfilled need
 Rick Jeliffe wrote > I note Ann Navarro's call for "An unfulfilled need" earlier this month, on a subject I also have been calling for for 2 years+: the need for a mechanism to bind information to names: "definitions, semantics, and other data that may be necessary to complete their operations." This looks to me like a case of two non-commercial voices being lost to more important voices. This view has also been expressed by The XML/EDI Group, and the recently formed CEN/ISSS Defining and Managing Semantics and Datatypes project team, but in this case they have been discussing them in terms of the semantics of electronic commerce. >I wonder if the reason can be found in Tim B-Ls recent post: > Rick Jelliffe: >>There is no W3C method to declare which schema should be >>used, akin to the stylesheet declaration. > Yes there is: resolution of the schema URI. >Tim is saying that using the namespace URI to specify a schema is the official W3C method. But there is nothing about this in any W3C spec; no working group has decided this or put it out in a public draft or spec. >On the contrary "It is not a goal that it [the namespace URI] be directly usable for retrieval of a schema (if any exists)" says XML NS. >That is a major architectural decision implied on top of namespaces; the only parties I see that can benefit from hardcoding schema URIs into namespace URIs are vendors, who could use this mechanism and only provide schemas in languages which they controlled or provided tools for: I don't think this is far-fetched-- Biztalk mandates XDR schemas only. One of the techniques the XML/EDI community have been propounding is the use of namespaced attributes to point to semantic specifications using the XLink mechanism or an application specific mechanism. Basically the namespace of the attribute points to the rules for interpreting the attribute value and the value of the attribute points to the definition of the semantics that are to be applied to the element. This way you do not need to rely on the namespacing of the element name - you simply indirect your element name into the name space of the semantics definer. Using this technique you can decouple the model language used for the message from any model associated with the semantics. This means that it does not matter how the semantics have been defined (XML-Data, RDF, text, etc) you can still use a DTD or a Schema to model your message. To me this gets over the problems that would arise if W3C tried to define formal mechanisms for the linking of namespace URIs to schemas, etc. Martin Bryan Warning: As I only have time to look at the weekly XML-DEV archive, and will be out of the country for the rest of this week, I may not reply in a timely function to any reactions to this message. ----------------------------------------------------------------- Martin Bryan, 29 Oldbury Orchard, Churchdown, Glos GL3 2PU, UK Phone/Fax: +44 1452 714029 E-mail: mtbryan@s... For more information about The SGML Centre contact http://www.sgml.u-net.com For more information about the European Commission's Open Information Interchange (OII) initiative contact http://www.echo.lu/oii/en/oiistand.html For more information about the ISIS XML/EDI Project contact http://wwe.tieke.fi/isis-xmedil.html 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
|
|||||||||
