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RE: Query decomposition [was: What niche is XQuery targeting?]

• To: "'Dare Obasanjo'" <dareo@m...>,"'XML Developers List'" <xml-dev@l...>
• Subject: RE: Query decomposition [was: What niche is XQuery targeting?]
• From: "Michael Kay" <mike@s...>
• Date: Wed, 15 Dec 2004 14:21:10 -0000
• In-reply-to: <830178CE7378FC40BC6F1DDADCFDD1D1027671FF@R...>
• Thread-index: AcTia1BPxPxNLyjjQZiWVI73DUa2KwAGQvhQAAikQAoAAlWd0A==

> So you want perform a query against a backend source that 
> only has a decimal numeric type using XPath which only has a 
> floating point numeric type.

Bad example, because XPath does now have a decimal data type. But of course
it's true that the operations in one query language won't always map
directly to the operations in another. However, translating expressions in
one language into equivalent expressions in a different language is a fairly
well-understood art; and in the area of query languages, there's decades of
research to fall back on. (I did my PhD on mapping of relational queries to
hierarchic data nearly 30 years ago - ironic that the interesting problem is
now the other way around...)


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

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  • RE: Query decomposition [was: What niche is XQuery targeting?]
    • From: "Dare Obasanjo" <dareo@m...>

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