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Re: XML aggregation question?

• From: Rick Marshall <rjm@xxxxxxxxxxx>
• Date: Mon, 28 Aug 2006 07:23:54 +1000

2 quick comments:

databases don't have to be a "load" any more than xml is a "load". there 
seems to be some sort of assumption that xml is instant and applies no 
load to a system, while an rdbms is anything but. not only is that not 
true, but xml may well be a significantly larger load than an rdbms for 
large problems.

xml might be a hammer, but not all problems are nails. one of the really 
great things about xml is that it can be used in so many ways - as the 
document, the data store, the glue between stores, to write programs 
(using xslt of course). etc. we should be flexible in this matter 
choosing best of breed technologies (one of which is definitely xml) 
when solving problems.

rick

Michael Kay wrote:
>> Based on all the comments thus far as well as reading some of 
>> the articles/documentation on eXist, it would seem that an 
>> XML database is really the only viable choice if I want to 
>> keep my data as XML and still provide aggregated views across 
>> the instances based on values of attributes (or other 
>> expressions using XPath and/or XQuery).
>>     
>
>
> This isn't absolutely true. For example, the W3C XSLT test suite (not
> published, unfortunately) is a collection of over 5000 XML documents held in
> filestore, and it's quite feasible to run queries in Saxon (using either
> XSLT or XQuery) across this collection. For example, to count how many of
> the stylesheets in the collection specify version="1.0" on the
> xsl:stylesheet element, use:
>
> count(collection('file:///c:/xslts_1_0_0/TestInputs?select=*.xsl;recurse=yes
> ')
>          [(xsl:stylesheet|xsl:transform)/@version='1.0'])
>
> What you don't get with this approach is performance. There's no database
> load operation, so there are no collection-level indexes: the system works
> its way through the directory parsing and testing each individual document.
> But it's still very useful (and surprisingly fast) for the occasional ad-hoc
> search.
>
> Michael Kay
> http://www.saxonica.com/
>
>
> !DSPAM:44f1f2de33197818312239!
>
>   

• References:
  • RE: XML aggregation question?
    • From: Michael Kay