Re: Basic XMLSchema questions
Alan Santos wrote: > > > > > > > Syntactically it appears to be legal to simply have <type> on it's own, > > Sorry, I meant to say <type name='xxx'>, I'm pretty clear on type now. > Thanks very much. > > You may have missed another question in a previous email.... > > At one point you had made a critical remark regarding XML schema to model a > class... > > "Your schema is one-to-one with a Java class? This wouldn't be a good > idea, unless I'm misunderstanding your intent. Maybe your _XML_ is > based on a class, and it specifies the class, but then multiple XML docs > (therefore multiple classes) all use the same Schema." > > Originally, this is what I was trying to use an XML Schema to do (that is: > store class info), and use an XML document to store instance values. (Sort > of a simplified XMI) I'll be very blunt; I think XML is great as a data representation. I think it is not quite there for mapping of objects. What you are talking about, I actually have built to a great extent in XML, so I can graph Java objects (and instances of those objects) for an XML-RPC application to talk across a network. I just don't think it is necessarily there yet. I still am not sure why you would want this graphing? Even in my XML-RPC, I found that most times it was worth the cost to completely graph an object/instance, it was worth using RMI. It was only when making procedural calls that returned simple primitives or very simple objects that XML-RPC shone (although it's highly recommended for those purposes). Why not use the schema for more of a constraining validation scenario? It is fairly simple to use almost the exact same XML document to represent both an object in general and an instance of said object. In fact, I could create a dirty XML map of an object, that could be "extended" (in this case, I mean elements added/attributes changed) without changing the original elements to represent any given instance. Then my schema is across all Java objects, ensuring that other apps can "understand" and de-map what I am sending them. All in all, a better solution, I think. Certainly faster... schema validation ain't quick yet ;-) Although with SAX2 I know that will improve much (b/c of standard interface - more heads = better solutions). > > I'm not sure I can do this, in any manner that doesn't break XML schemas. > There doesn't appear to be a mechanism in place to expand the functionality > of XML-Schemas As Henry pointed out, there are what I would consider "hacks" and "back-doors" that make it *possible*. > > But if it is possible, I'm interested in why you feel this is a bad idea? I think you are better to do this sort of thing in raw Java. Of course, I still haven't seen what you are trying to accomplish, so maybe that would help ;-) -Brett > > (BTW, I think this is similar to what was done with Quick) > > Finally, . > > thanks, > alan 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 unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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