--- Stefano Mazzocchi <[EMAIL PROTECTED]> wrote:
> Dare,
> 
> thanks much for your effort on SiXDML. I've
> submitted it for review to
> the JSR 170 (Java Repository API) where I'm the
> official Apache
> representative. We'll see what happens.

The XML:DB initiative site is down now but I'd like to
find out what you submitted. The API and the language
although once tied together are now seperate. Also, I
shall be creating another version of the API
(basically a level 1A & level 1B conformance level
that are orthogonal to each other). 

Level 1B will be the current API while Level 1A will
be an API similar to ODBC & JDBC that is geared
towards executing commands passed as strings or
parameters. 

> 
> I have a question for you: what does it mean to run
> a 'select' query
> thru an XQuery transformation stage?
> 
> I understand perfectly the XSLT case (which might be
> interesting for
> server-side optimizations, even if I think that
> transformations normally
> happen at another level).
> 
> The XPath and XQuery samples used as a transforming
> post-process are
> puzzling me. Can you give me your thoughts on this.

Currently XPath 1.0 is not sophisticated enough for
complex queries and it doesn't perform
transformations. Both XSLT and XQuery in its current
can be used for complex queries and transformation. 

However with the advent of XPath 2.0 which currently
looks like it will be a large subset of XQuery then
the need to create such layering of query engines will
be unnecessary. 
  
Piping query results to XSLT and other query engines
may be expensive performance wise since the way I
originally conceived it involves obtaining all the
results from the XPath query then passing those to the
XSLT or other engine and in fact that's how it is
currently implemented in the reference implementation.


Efficient implementations would have to either stream
the XPath results to the other query engine or
integegrate both engines tightly to boost performance.


Another issue may be crop up if future versions of
XQuery support updates. I currently am unsure of how
to solve this problem but since it is currently
theoretical, I haven't given it much thought. 


=====
THINGS TO DO IF I BECOME AN EVIL OVERLORD #145
My dungeon cell decor will not feature exposed pipes. 
While they add to the gloomy atmosphere, they are good conductors of vibrations 
and a lot of prisoners know Morse code.

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