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   Re: [xml-dev] Adam Bosworth Article - what does "directaccess"m ean?

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Jonathan Robie wrote:

> >and 5) [most crucial of all unexamined assumptions here] presupposed to be
> >in a form against which the computation expressed in the code is directly
> >executable (though, of course as 'real' XML the only form that they would
> > necessarily be in is Unicode text).
> No, the XQuery I showed you does not make this assumption.
> The data might be in an XML document that can be accessed and parsed using the
> document() function, or it might be in a view of some other resource such as a
> relational database.

I'm sorry, Jonathan, I don't understand. What is

    return $stock/price / ($stock/revenues - $stock/expenses)

except the execution of subtraction and division arithmetic operations against the
'values' of $stock/price, $stock/revenues, and
$stock/expenses? And if your query is against XML, then the values of those items
are runs of Unicode text, and your arithmetic operations are effectively
meaningless. But I'm afraid it is as you and I discussed in Baltimore:  what you
are doing here is not querying XML but querying a database through an 'XML view'
as if this XML-encoded query language were a sort of SQL. In other words, what is
'XML' here is a framework for instantiated data in the internal numerical
representation which both your data sore and your query writer implicitly agree
on. Nothing is parsed, because nothing here is *really* XML, which would have to
be instantiated on the output of a parse as the data structure that your
arithmetic operations require. Or am I misunderstanding entirely?


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