Re: [xml-dev] Were these derived from a logical data model: XSLT, XML Sc

[Liam Quin <liam@w3.org>]

On Sun, Mar 16, 2008 at 07:51:33AM -0400, Costello, Roger L. wrote:
> I am interested in knowing if these XML vocabularies -- XSLT, XML
> Schema, XHTML, Schematron -- were developed by first creating a logical
> data model.

XPath 2.0, XSLT 2.0 and XQuery 2.0 do use a logical (abstract)
data model to describe XML.

It is not a traditional entity-relational diagram as you depicted:
those are oftn used when designing a schema, but not so often
when designing a schema language.

So...

> I wonder how often people designing XML vocabularies follow that
> methodology?
Yes, or something like it, and have done for many years.
Atlas Consulting (or was it Atlas) published one such methodology;
Microstar had another.

> I wonder if XSLT, XML Schema, XHTML and Schematron were
> developed by following that methodology?
> 
> DERIVED FROM A LOGICAL DATA MODEL?
> 
> 1. XSLT: the XSLT specification [1] describes an XML vocabulary that
> can be used to create a stylesheet.  It describes what tags can be used
> and the meaning of each tag, i.e., how an XSLT-aware application will
> behave when it encounters each XSLT element.

No.  XSLT describes what *elements* can be used; it is not defined
at the lexical level of start and end tags.

But, XSLT 2 is built on a logical data model, although not one
described in terms of relational algebra.

Liam


-- 
Liam Quin, W3C XML Activity Lead, http://www.w3.org/People/Quin/
http://www.holoweb.net/~liam/ * http://www.fromoldbooks.org/