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See below.
Best regards
Michael
> -----Original Message-----
> From: Bullard, Claude L (Len) [mailto:len.bullard@intergraph.com]
> Sent: Monday, April 18, 2005 9:07 AM
> To: Michael Rys; 'Ronald Bourret'
> Cc: 'xml-dev@lists.xml.org'
> Subject: RE: [xml-dev] XML-enabled databases, XQuery APIs
>
> What would be the consequences to XML datatypes in relational
> databases should an XML binary standard be created?
[Michael Rys] See my other response.
> What is the efficiency or effectiveness of the indices and
> queries given radically different kinds of XML document types
> (eg, querying over a business document in XML vs a vector
> graphic in XML)? Or put another way, how does the document
> type as instanced in the XML datatype affect querying performance?
[Michael Rys] Well, that depends heavily on the type of queries that you
plan on running. The answer is about the same as if you would ask me
about how efficient or effective the indices and the query optimizer is
for different kinds of relational schemata (OLTP, OLAP, lots of tables
with lots of columns etc.).
It certainly does affect it, but the question at the moment should be
more along the lines of: If your data fits the relational model and all
you need is a relational processor, should you store the data as XML or
should you shred it. And my answer today is: Just shred it.
> Thanks Michael. I look forward to the publication of the paper.
> Please post a note to the list when that happens.
[Michael Rys] Will do.
> len
>
>
> From: Michael Rys [mailto:mrys@microsoft.com]
>
> Good picture :-).
>
> Although you can also use indices to find branches inside the trees
> using XPath/XQuery...
>
> Dana Florescu, Don Chamberlin and I have organized a tutorial for
SIGMOD
> later this year that talks about the different ways relational
database
> systems (and the different vendors) are providing XML support (both on
> the functional level as well as architectural implementation details).
> It will talk among other things also about what it generally
considered
> shredding and BLOB storage vs different degrees of XML storage
> fidelities. Note that a node table representation is a shredded
storage
> of XML but provides XML Infoset/Data model fidelity. And it can be
> implemented efficiently as our implementation shows.
>
> Once SIGMOD puts the material online, I will post a link on my weblog.
> The tutorial follows my book chapter in the "XQuery from the Experts"
> book
>
(http://www.amazon.com/exec/obidos/ASIN/0321180607/musionxmlxque-20?crea
> tive=125581&camp=2321&link_code=as1) in case you cannot wait. :-)
>
> Best regards
> Michael (http://sqljunkies.com/weblog/mrys)
>
> PS: And no, XML in a relational database is not any more a hack than a
> so-called native XML database....
>
>
> > From: Bullard, Claude L (Len) [mailto:len.bullard@intergraph.com]
>
> > And that makes sense. I have this mental image of a
> > 2D table pasted to a wall and each cell map to a brick.
> > If you walk behind the wall, you see little trees growing
> > behind some of the bricks.
> >
> > Use the relational index to find the tree in the
> > forest. Use XPath or XQuery to walk the tree
> > fetch a leaf or saw off a branch.
> >
> > Thanks Ron.
> >
> > len
> >
> >
> > From: Ronald Bourret [mailto:rpbourret@rpbourret.com]
> >
> > Another way to think about all of this is that the XML data type is
> the
> > exposed tip of a native XML database embedded inside a relational
> > database.
> >
> > Clear as mud?
> >
> > -- Ron
> >
> > Bullard, Claude L (Len) wrote:
> >
> > > I don't understand this nearly well enough. In a
> > > relational database, what are the characteristics
> > > of an "XML type"?
> >
> >
> >
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