[sc34wg3] Topic Maps land and SAM land

[Sam Hunting]

Martin:

Thanks. I just wanted something to mull over (besides the original John
Sowa quotations at:

http://mars.virtual-earth.de/pipermail/cg/2001q3/003835.html ("I have
never been happy with the notion of 'data model'...") and at
http://mars.virtual-earth.de/pipermail/cg/2001q3/003844.html ("there is no
clear notion of a data model"))

> > of "metamodel" has gone unanswered as well. Of course, maybe the word is
> > only there for marketing purposes, so I shouldn't concern myself with it.
> 
> Try the following from Table 2.1 of the OMG Unified Modelling Language:
> 
> Metamodel: Defines the language for specifying a model
> 
> or the definition given in the OMG Modeling Glossary in Annex B of the
> specification:
> 
> "A model that defines the language for expressing a model."
> 
> (I prefer the first as the second is circular.)

> In fact UML also defines metamodel as "An instance of a meta-metamodel"
> where a meta-metamodel is defined as "The infrastructure for a metamodelling
> domain" and defines a model as "Describes a language to define an
> information domain".
> 
> Whether or not you consider the use of the term metamodel within UML (which
> is littered with the term) as an "agreed-upon definition" is up to you.

Well, it seems there are three (one of which is circular) so there are two
available to us. Which one do we use? Unless, of course, we have a fourth
definition. Or indeed if the term is just in the text for marketing
purposes and I don't have to obsess about it. In the former case, I guess
it's not an issue, since it would be subsumed under the larger task of
writing the glossary for the SAM. In the latter case, it isn't an issue
because "data model" just becomes a phrase that achieves a certain comfort
level for an audience (as Sowa puts it), rather than a term -- not that
there's anything wrong with that.

Martin -- "Be open to the possibility that being is!" 



> Martin Bryan
> IS-Thought: Thinkers for the Information Society
> 29 Oldbury Orchard, Churchdown, Glos. GL3 2PU, UK
> Phone/Fax: 01452 714029 E-mail: martin@is-thought.co.uk
> 
> Thought of the week:
> Is "being" necessary? Won't "known as" suffice?
> 
> 
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> 

Sam Hunting
eTopicality, Inc.

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