[xquery-talk] Release of the GCX XQuery EngineQ

[Marc Van Cappellen]

Actually, DataDirect XQuery supports document projection, and at the
same time also implements what is called in this thread "streaming
XQuery evaluation".

And with all this, DataDirect XQuery is reasonable conformant to the
XQuery specification, the XQTS results have been published.

As indicated by Michael in some other email on this thread, streaming
XQuery evaluation can't be applied to all scenarios. As such DataDirect
only (or does not) applies it in specific scenarios.

I hope this helps,
Marc 

> -----Original Message-----
> From: talk-bounces at x-query.com [mailto:talk-bounces at x-query.com] On
Behalf
> Of Stefanie Scherzinger
> Sent: Monday, February 05, 2007 9:09 AM
> To: Michael Kay
> Cc: talk at x-query.com; Michael Schmidt
> Subject: Re: [xquery-talk] Release of the GCX XQuery EngineQ
> 
> Hello Michael,
> 
> thanks for your interest in GCX.
> 
> Regarding your comments on query rewrites: Yes, we've restricted
> ourselves to a maneagable syntactic fragment of XQuery for a start,
> and we're confident that the fragment can be extended. The static
> query rewriting which inserts the "signOff-statements" into queries
> from our fragment is already implemented in our engine.
> 
> > As far as I can see, what they have done is a useful development
that
> takes
> > further the idea of document projection put forward by Marian and
> Simeon,
> > which is already being exploited in industrial products such as
> DataDirect's
> > (though not yet in Saxon, regrettably). This work also,
incidentally, is
> > likely to convince any sceptics that a language with restricted
> expressive
> > power compared to XSLT is capable of being optimized to a much
greater
> > extent than XSLT is, which helps users in understanding the
trade-off
> > between the two languages.
> 
> Thanks for the pointer to DataDirect, I didn't know they had
> projection implemented. I've been looking a bit into optimization
> techniques for DOM trees, and came across the TinyTree model from
> Saxon. I  was wondering whether you plan to keep extending it.
> 
> Steffi
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