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Re: XML: logical and/or physical model?

• To: xml-dev@l...
• Subject: Re: XML: logical and/or physical model?
• From: Eric van der Vlist <vdv@d...>
• Date: Fri, 28 May 2004 16:00:15 +0200
• In-reply-to: <D7C51D33-B0AC-11D8-87B8-000A95CCC59E@x...>
• Organization: Dyomedea (http://dyomedea.com)
• References: <D7C51D33-B0AC-11D8-87B8-000A95CCC59E@x...>

On Fri, 2004-05-28 at 15:42, Michael Champion wrote:

> So, my  question is whether this characterization of XML as an  
> essentially physical model rather than a logical one makes sense? Of  
> course, the Infoset and XQuery treat XML as a logical model that is  
> independent of the "physical" serialization or DBMS implementation, so  
> what I'm talking about is more of a design pattern for using XML than  
> an intrinsic property of XML itself, and is independent of whether one  
> thinks of XML as a labeled tree data structure or Unicode text with  
> angle brackets.

IMO, what we used to call "physical data models" for RDBMS were at the
exact same level than the XML Infoset. They didn't expose how the bits
were physically stored in the database but what the tables looked like
exactly like the XML Infoset describes what the labeled trees look like
but not how they should be stored and serialised.

In fact, I think that people still have to agree on standard
representations of logical data models for XML like they did in the past
for RDBMS.

Schema languages are certainly not logical data models either and UML is
probably the best choice at the moment, except that we lack a standard
set of XML specific stereotypes to describe XML infosets.

Eric
-- 
See you in Portland.
                               http://conferences.oreillynet.com/os2004/
Upcoming XML schema languages tutorial:
 - Portland   -half day-   (27/07/2004)        http://masl.to/?E6ED13728
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Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(ISO) RELAX NG   ISBN:0-596-00421-4 http://oreilly.com/catalog/relax
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
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• References:
  • XML: logical and/or physical model?
    • From: Michael Champion <mc@x...>

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