[xquery-talk] A Couple of Questions - OOXML and SQL

Michael Kay mike at saxonica.com
Thu Apr 3 20:13:01 PST 2008

1. It's certainly possible to get meaningful information out of Microsoft
Office XML formats - but it's not easy! I haven't used XQuery on this, but
I've done it using XSLT 2.0, making fairly heavy use of the positional
grouping facilities which have no direct equivalent in XQuery 1.0; I think
that for this kind of data structure XSLT's template rules are also very
useful. So my first choice would have been XSLT rather than XQuery. However,
the degree of difficulty depends very much on what information you are
hoping to extract, and on the degree of regularity present in the input
2. XQuery doesn't currently have update support (though it's coming soon and
is available in some products). But you'll find equivalents to most of SQL's
set operators in XQuery. It's a different data model (sequences rather than
sets, hierarchies rather than tables, nodes with identity rather than only
values), so the details are obviously rather different. But one could argue
that the SQL operators (with some exceptions such as "group by") drop out as
a subset of the XQuery operators.
Michael Kay


From: talk-bounces at x-query.com [mailto:talk-bounces at x-query.com] On Behalf
Of Tsao, Scott
Sent: 03 April 2008 13:30
To: talk at x-query.com
Subject: [xquery-talk] A Couple of Questions - OOXML and SQL

During a recent XQuery Overview presentation, there were a couple of
questions raised which I am searching for answers:
   1. Office Open XML (OOXML) is a file format used by the Microsoft Office
2007 applications. Can XQuery be used to get meaningful information from an
OOXML document, or would it only return items based on formatting aspects
(all heading 1s, or all list items).
   2. SQL is based in part on Set theory from Mathematics, and Set algebra.
It allows set operations "update all red projects to green." Does XQuery
support set algebra? For example, SQL join is a set operation that has
inner, outer, Cartesian forms. http://en.wikipedia.org/wiki/Algebra_of_sets
Do you have answers to those questions? If you do, please do share!

Scott Tsao 
Associate Technical Fellow 
The Boeing Company 

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