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What would be the consequences to XML datatypes in relational
databases should an XML binary standard be created?
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?
Thanks Michael. I look forward to the publication of the paper.
Please post a note to the list when that happens.
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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