Colloquium at Stanford
The Unfinished Revolution

Memorandum


Date: Sun, 20 Feb 2000 17:20:51 -0800

From: Eric Armstrong Reply-To: unrev-II@onelist.com

To: eXtenDE-dev , "unrev-II@onelist.com"

Subject:   Data Modelling

I just got this interesting pointer from another list. Anyone familiar with it, or willing to give it a look?

The referenced page lists a number of books, at least one of which is by Martin Fowler, so it is must be real...

From: Kjell Bengtsson

For avanced mapings you may consider the ISO 10303 standards. There you will find both a formal data modelling langauge EXPRESS and a declarative mapping langauge EXPRESS-X. As for implementations you can access both models (schemas) and data sets by Java (part 27) and XML (part 28).

I am convinced that ISO 10303 and Express-X will solve your mapping concerns. Then you can link in these pieces of software into your applications.

(You can find more about ISO 10303 at :

http://www.epmtech.jotne.com/learn/index.html

Best regards, Kjell

From: Sylvia Fang [SMTP:FangSH@PEBIO.COM] 

I'm trying to design DTD for data exchange between several applications. These applications look at these data with different perspectives. For example, one might be interested in knowing students in a class:

!ELEMENT SCHOOL (CLASS)+>
!ELEMENT CLASS (STUDENT)+>
!ELEMENT STUDENT (ORGANIZATION) >
!ATTLIST STUDENT

name CDATA #REQUIRED>

Another might be interested in knowing students in extra-curricular organizations:

!ELEMENT SCHOOL (ORGANIZATION)+>
!ELEMENT ORGANIZATION(STUDENT)+>
!ELEMENT STUDENT (CLASS) >
!ATTLIST STUDENT

name CDATA #REQUIRED>

The data content is the same, but with different groupings. Is it possible to design a flexible DTD such that each application doesn't have to traverse and re-structure the tree?


Sincerely,


Eric Armstrong
eric.armstrong@eng.sun.com