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Jon Cleaver wrote: > > There appears to be a convergence of thought that the design of an XML > schema is somewhat analogous to the creation of an Object Oriented Design > for a piece of code. There are instances where you want to maximise > component reuse and instances where you want data to be private. There are > also instances where you want to combine both of these. While I do see the similarities, there also seems to be one big difference. In OO design, you can hide data inside an object and tell everybody else that they can't see it. In XML, the data is in full view, even if the element type definitions are local. All of which makes me wonder why XML Schemas defined local element types in the first place. Except for namespace hiding (which I hadn't thought of), the only application I could see was a direct mapping of Java classes to XML Schemas -- local element types would solve the problem of two different classes having properties of the same name without having to resort to per-class namespaces. (As an aside, this is, IMHO, exactly why namespaces turned out to be so hard. In programming languages, you have many levels of "local", and a compiler can decorate names to ensure global uniqueness. All very nice and hidden from a programmer. In XML, everything is in full view and the schema author has to do the decoration manually.) -- Ronald Bourret Programming, Writing, and Training XML, Databases, and Schemas http://www.rpbourret.com
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