Re: [xml-dev] Stability of schemas -- frequency of versioning

[Liam R E Quin <liam@w3.org>]

On Mon, 2011-11-21 at 12:58 +0000, Costello, Roger L. wrote:

> Suppose, however, that the information for a domain is required to
> frequently change, say, three times a year. 

Generally there are constant or slowly-changing aspects, otherwise one
wouldn't be able to characterise the domain at all.

So you can develop a framework that's constant.

For example, you might run a school with a list of students. You could
have a rigid structure:
    <chemistry year="3">
      <david/>
      <nicola/>
      <simon/>
    </chemistry>
but if you did that, you'd have to change the schema each term
(semester), or whenever a new pupil arrived or a current one left.

So it would be better to have
    <chemistry year="3">
      <student>David</student>
and so on, or,
      <student ref="david" />
and have a list of student records.

Now the school will need to change the schema if the list of courses
changes, and they may want to abstract those too.

If there are really no constants, if everything changes unpredictably,
get the hell out of there. Quicksand is dangerous, and you could lose
your shoes!

Liam


-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/