Re: [xml-dev] XML and the Relational Model (was Re: [xml-dev] A standard approach to glueing together ...)

From
Bob Foster <>
To
"Hunsberger, Peter" <>,
Date
2003-08-27T23:31:34Z
ID
<0f6f01c36cf3$5a8c9040$6401a8c0@snobird>
Thread
Re: [xml-dev] XML and the Relational Model (was Re: [xml-dev] A standard approach to glueing together ...)
From: "Hunsberger, Peter" <>
>I'd propose that an XPath statement in general can be considered the XML
>equivalent to a view...

That's a reasonable idea. It should be understood that the type of such a
view is a (not regular) hedge, that is, a sequence of zero or more (not
regular) trees.

Since it's desirable that views have the same type as the data they are a
view of, you would be led to consider XML data to be a (not regular) hedge,
as well. For example, a sequence of zero or more arbitrary documents is such
a hedge. This makes sense, since an XPath 2.0 expression can operate upon
zero or more documents, as well as other named hedges.

Taking a view via XPath would then be a closed operation. This addresses an
issue raised here earlier by Murali Mani.

Bob Foster