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RE: Multiple Inheritance in XML Schema

• From: "Michael Kay" <mike@s...>
• To: <abcoatesecure-xmldev@y...>,"'XML-dev'" <xml-dev@l...>
• Date: Mon, 29 Dec 2008 19:11:14 -0000

> On Wed, 24 Dec 2008 08:18:00 -0000, Ramkumar Menon 
> <ramkumar.menon@g...> wrote:
> 
> Why isn't there a straightforward mechanism for multiple inheritance 
> in XML Schemas?

> > What are the rationales for that design decision?

Please note that XSD 1.1 allows an element to participate in more than one
substitution group, which may solve your problems. Also, you can achieve
many of the effects of multiple inheritance by using named model groups (or
attribute groups) - which is more like a delegation mechanism than an
inheritance mechanism, but it achieves the desired reuse.

As for the rationale, I have often said that it can be difficult to work out
why a committee made a particular decision even when you were present at the
meeting where the decision was made. If you want a historically correct
answer to a question like this, you first have to trawl through the minutes
to discover whether a proposal was ever made and rejected; if no proposal
was made, then you have to ask each of the members individually why they
didn't make one...


Michael Kay
http://www.saxonica.com/

• References:
  • Multiple Inheritance in XML Schema
    • From: "Ramkumar Menon" <ramkumar.menon@g...>
  • Re: Multiple Inheritance in XML Schema
    • From: "Anthony B. Coates (XML-Dev)" <abcoatesecure-xmldev@y...>