Cart
[Home] [By Thread] [By Date] [Recent Entries]
----- Original Message ----- From: "Nicolas Lehuen" <nicolas.lehuen@u...> To: "Clark C . Evans" <cce@c...> Sent: Monday, January 21, 2002 11:36 PM Subject: Re: Re: RDDL -- How would you design it? > > Questions for the model... > > > > a. Can a Document belong to more than one Class? > > This is a difficult question. Life would be much easier if the answer was > 'no', but we should think about it and find solid reasons to support this > 'no'. > > > b. Can a Bundle have Resources from more than > > one Class? If so, is Directory redundant? > > c. Can a Class have more than one Bundles? > > Well in fact, I'd rather have a Directory per Class, with no Bundle, for the > sake of simplicity. I'd like the Directory to be referenced as an URL, so > that different Classes from the same domain (same application or same > semantics) could have their Directories at URL from the same domain, > possibly with a common root path. > > The resolution of a meta-data resource will use at least three adressing > schemes : > > 1) From a document to a document Class (depending on some information in the > document) > 2) From a document Class to a Directory (depending on the Class URL) > 3) From a Directory to a meta-data Resource (depending on the Resource Class > URL ?) > > If we had bundles and multiple class support per Directory, the adressing > schemes will become more complicated, and feature more stages, for example : > > 1) From a document to a Directory (depending on some information in the > document) > 2) From a document to a document Class (depending on some information in the > document) > 3) From a Directory to a Bundle (depending on the document Class URL) > 4) From a Bundle to a meta-data Resource (depending on the Resource Class > URL ?) > > I'd rather not have this extra level of complexity. > > > d. Are authorities attached to Resources or Bundles? > > Are Authrorities even necessary? > > Like I said before, I'd rather let the authentication problem to someone > else, not trying to solve this problem at the meta-data level only. There > are some initiatives like XML Signature whose purpose is to provide methods > for authentication and forgery protection. Let them handle this, and use > their solutions both at the document and meta-data level. > > > Questions for an XML version of the model... > > > > 1. Are Classes namespace URIs? Are all URIs a Class? > > Dunno and nope. To begin with, an URI is not a Class, a namespace, a > document or whatever. I know by experience that it's annoying to be > corrected on this point if you're already aware of the difference, but I > have to make sure we agree on this point. A URI is basically a string of > characters, specified by RFC 2396, which can be resolved into a resource > (hence my hesitation to use Resource as the name for meta-data documents). > > Then, regarding your first question about how are Classes related to > namespaces and namespaces related to Classes (I assume you meant that), I > cannot reply. I just posted another mail with the subject "Finally, what if > namespaces == document types ?" that try to explain my position. Anyway, in > the *current* state of XML specs, XML Schema excepted, there are no > relations between Classes and namespaces. > > > 2. If URIs are classes, is the document's Class the > > namespace of the root element? Is it's collection > > of classes (if A is yes) the collection of namespaces > > within a XML document? > > Same thing for your first question. For your second question, I think the > answer is definitely no, because if a document has multiple classes (which I > believe is no, but I have no reasons for the moment apart that it would make > our life bearable), and if classes were related to namespaces, I don't see > how the set of classes of a document would be related to the set of > namespaces it contains. I guess that if a document had multiple classes, all > classes would reside in the same namespace. > > Hum... I think this gives an idea of how a document could have multiple > classes. A document would be said to belong to a class if it matches a > schema associated to the class. If the document matches multiple schemas, > then it belongs to multiple classes. This could be something to investigate. > > Regards, > Nicolas >
|
