[sc34wg3] 4.3 Constraints

Patrick Durusau sc34wg3@isotopicmaps.org
Thu, 20 Nov 2003 07:58:25 -0500


Lars Marius Garshol wrote:
> * Patrick Durusau
> | 
> | 


> Well, the thinking is that *every* topic map standard will follow the
> DM, and that if it doesn't it won't be a topic map standard, but
> something else. Also, I don't think such a declaration will be of much
> use if you don't trust the authors to be able to follow the DM, since
> then you can't trust the declaration either.

Well, does the same reasoning apply to an application that performs 
merger in ways not specified by the data model? Does that make it 
"something else?"

As you know I don't buy the argument that the data model defines all 
things that are topic maps, or even topic map standards but I am trying 
to leave that aside for the moment as I don't think either of us will 
convince the other of our respective positions.

I really do think that for many purposes, including standards, the data 
model is a good thing. My concern is for cases, some have been mentioned 
on the list, where user requirements seem to be straining the standards 
that will (eventually) be based on the data model.

What do we tell users who sincerely think that their data models cannot 
be fitted into the TM data model? My impression has been, not based on 
anything in the data model but informal conversation, that departures 
from the data model are possible, should such cases arise. (Realize we 
will disagree on the likelihood of such cases but humor me for the moment.)

Make no mistake, I think having a standard for implementing topic maps, 
even if it is only our current view of how that should be done, is a 
very important thing. And that standards, such as constraint and query 
languages, of necessity must be based upon an implementation view of 
topic maps. Would be hard to imagine otherwise.

Take a fairly likely senario within the DM governed standards: The TMDM 
is post FDIS as 13250-2. We are all (still) working on TMQL when we 
discover the need for something that was not included in 13250-2. We 
want to be conformant with 13250-2 but we have to add something in TMQL, 
which of necessity makes us out of conformance with 13250-2. Are we then 
working on a non-topic map standard? I would say no and suspect you 
would agree.

That is why I think the W3C method of claiming conformance is to be 
preferred. I don't think we can, or that any standards group can, 
imagine all future events. Acting as though our current experience is 
the definition of an activity, given the rate of change in technology, 
is untenable.

> | BTW, I missed the "constraints on the allowed instances of the
> | model" part. Pointers anyone?
> They are listed throughout the document. Just search for "constraint"
> and you'll find them.
Well, that's certainly helpful. ;-) Actually I recently grabbed a 
concordance program that I have begun loading drafts, etc., into for 
generating KWIC indexes.

What I was looking for were statements to the effect that "one must 
implement ...." etc. In other words, what if I draft a standard for 
PSI's that does not have associations? Are topic maps required to have 
associations? Does that omission make my standard a non-topic map standard?

I was reading "allowed instances of the model" to mean that somewhere 
there was a definition of how much of the model or in what combinations 
it could be implemented. And still conform to the TMDM.

Hope you are having a great day!


Patrick Durusau
Director of Research and Development
Society of Biblical Literature
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model

Topic Maps: Human, not artificial, intelligence at work!