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RE: Are we losing out because of grammars?

It has been stated for some time from experience with 
large data systems in CALS:

1.  Monolithic DTDs failed generally to be workable 
both in production and in maintenance.

2.  Parameter entities bought little but naming 
sugar for the DTD maintainer

3.  Most systems are better expressed in families 
of definitions with links among the definitions for 
named relationships (say over containment for a weak 
IS-A or HAS-A)

So, not exactly a new requirement.  Some thought 
modularity was the right approach, but it is only 
part of it.  Modularity bought us smaller table level 
definitions, but not interrelated tables as are typical 
of parent/child tables.   The issue has been 
that as was stated in another thread, people have mostly 
built small XML systems and have yet to tackle the 
problems of large interrelated sets.   

Again, and as I asked James and Rick, step back 
and look at this in terms of very large pipelines 
of information moving among agencies and consider 
the costs of creating models that have to be shared 
and among which, pieces of the data migrate.

Len Bullard
Intergraph Public Safety

Ekam sat.h, Vipraah bahudhaa vadanti.
Daamyata. Datta. Dayadhvam.h

-----Original Message-----
From: Eric van der Vlist [mailto:vdv@dyomedea.com]
Sent: Sunday, January 28, 2001 7:54 AM
To: xml-dev@lists.xml.org
Subject: Re: Are we losing out because of grammars?

"Clark C. Evans" wrote:
> Actually... I've found that I can't do anything without
> some sort of linking.  Even the most trivial timesheet
> example is a graph structure, else you have de-normalized
> the information.  Certainly if you do any relational database
> interaction you are definately in the world of graphs,
> partial information, and network databases.

"Links" are key for any information system and XML is no exception ! 

Without "links" (taken in the general meaning of the word) a RDBMS would
be nothing more than a set of spreadsheets.

<advert kind="shameless">
Practical ways to express links with XML is the subject of an article I
have written for XML.com [1] and of the tutorial I will be delivering at
WWW10, XML Europe 2001 and (if my submission is accepted) XTech 2001.

> Perhaps Rick is on to something here.  Are we modeling the "parts"
> without looking at the "whole"?  Can one truely have a
> schema for a single document type?  Or must a schema necessarly
> model a set of inter-connected document types.

Yes, that would be really great to have schema languages that let you
describe the links within and also between documents.

XML Schema languages seem to focus on single documents and this looks
also like a necessary extension !

> By far the most interesting (and practical) thread in months,
> Clark

[1] http://www.xml.com/pub/a/2000/10/04/linking/index.html
Eric van der Vlist       Dyomedea                    http://dyomedea.com
http://xmlfr.org         http://4xt.org              http://ducotede.com