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At 11:03 AM 5/7/2002 -0700, Dare Obasanjo wrote:
>I don't understand why you continue to miss my point. My original
>assertion which started this thread was that the XQuery WG was and is
>incorrect in stating that a static type system is necessary to add DML
>semantics to XQuery.
I never said it was necessary, but I do believe it to be desirable.
If your updates would create invalid data, they should fail dynamically.
But if they are going to fail dynamically, and a static type system can
tell me that, I would rather see the error today, *before* I ship my new
query library to a thousand users whose data may be different from my test
cases.
>The fact of the matter is that regardless of all the complexity you place
>on implementors (which will probably lead to a "Can anybody implement
>XQuery?" thread on XML-DEV in 12 months) the fact of the matter is that
>DML will still require post-update validation in a wide range of cases.
In fact, I think it reasonably likely that many of the early
implementations of XQuery will not implement the static type system, and I
also think it likely that the XML Query Working Group will make static
typing optional for implementations. Personally, I expect reasonably good
support for the dynamic typing.
I agree with you that implementability is an important criterion. Who can
implement XQuery? Well....
Cognetic Systems: http://www.cogneticsystems.com/xquery/xquery.html
Enosys Markets: http://www.enosysmarkets.com/products/xq.html
Fatdog: http://www.fatdog.com/
Ipedo's XML Database v3.0: http://www.ipedo.com
IPSI-XQ: http://xml.ipsi.fhg.de/xquerydemo
Lucent: http://db.bell-labs.com/galax/
Microsoft: http://xqueryservices.com
OpenLink Software (Virtuoso Universal Server):
http://demo.openlinksw.com:8890/xqdemo
Oracle: http://otn.oracle.com/tech/xml/xmldb/htdocs/querying_xml
Qexo (Kawa-Query): http://www.qexo.org/
Software AG: http://www.softwareag.com/developer/downloads/default.htm
Sourceforge's Kweelt: http://kweelt.sourceforge.net/. Open-source.
SourceForge's XQuench: http://xquench.sourceforge.net/. Open-source.
X-Hive: http://www.x-hive.com/xquery
XML Global: http://www.xmlglobal.com
> Secondly, if XQuery wasn't so wedded to W3C XML Schema, the W3C wouldn't
> be forcing users of XQuery to also become users of W3C XML Schema but
> instead would allow them to use whatever XML schema technology they liked
> including DTDs and RELAX NG.
XQuery will have explicit support for DTDs, well formed XML, and schemas. I
think it will probably be possible, but challenging, to define a RELAX NG
mapping.
For all of these, I do think that using the XML Schema built-in types is a
strength, not a weakness. You really do want to know what an integer is.
Jonathan
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