[utypes] Wild edit towards more principled definitions

[Laurent Michel]

Dear all,

I would go back to the  Markus's proposal on the Obs Core Component DM document.

I agree with the will of keeping the utype definition independent of any formalism.
But that should not imply to reduce the DM definition to an acyclic graph as said page 5.
I might have misunderstood the scope of the model definition given here, but I believe that it must be clarified,
A DM contains quite more information than a graph can do. Semantic information is for instance completely ignored by the graph. 
The exact nature of vertex (class or role) is also skipped.
As I understand, The graph as  shown in the document is rather a view of a DM (a class diagram is another one) allowing to 
construct UTypes independently of any formalism which is a good point
I propose to suggest DM designers to provide such graphs with their models. That could very helpful to ensure the consistence 
between UTypes and the DM they come from,  but we can not consider graphs themselves as model definitions.

Cheers
LM


On 14/12/2011 16:54, Markus Demleitner wrote:
> Dear colleagues,
>
> As those of you who followed my talk in Pune
> (http://docs.g-vo.org/talks/2011-pune-utypes.pdf) may have feared (or
> hoped; there were some approving gestures back at the talk), I've now
> spent some quality time rewriting the chapters 2-4 for the utype
> specification.
>
> Since I'm aware that what I did probably is not 100% popular, I've
> branched the volute utypes repo; for now, I'm working on
> https://volute.googlecode.com/svn/branches/utypes-experiment.  You're
> welcome to commit there (honestly!), too, but I'd leave merging stuff
> to trunk to Omar (unless he tells me otherwise).
>
> Since the build dependencies of the document are a bit larger now
> (you need the algorithm package and friends), I've put up a pre-built
> PDF at http://docs.g-vo.org/utypes-md.pdf.  As I said, I've basically
> touched chapters 2-4 only, so that's all I'm soliciting feedback
> for for now (so that's less than 5 not very dense pages for you to
> quickly go over).
>
> The diffs (svn diff -r 1623
> http://volute.googlecode.com/svn/branches/utypes-experiment) aren't
> all that helpful this time, since I've basically replaced the
> chapters.  For future diffs, though, I'd appreciate if the source
> in trunk could be formatted with lines of about 72 chars length --
> with the current oversized lines, the diffs will be hard to read,
> and merges unnecessarily troublesome.  Omar?
>
>
> Anyway -- *if* people can imagine that this is a step forward, my next
> plans (for the new year, presumably) would be to
>
> * change "data model re-use" to suggest VOTable groups or similar but
>    defer much of it to the container format
> * add a (short) chapter on values serialization saying that the values in
>    utype/value pairs are always strings and a bit more on top of that
> * write an appendix "serializing data model instances in VOTable"
>    that will try to specify more or less the principles behind the
>    STC in VOTable method
> * find space for prefix:DataModel.URI and other nitty-gritty.
>
> If, on the other hand, you think I'm mad and you'll never agree to
> such extensive changes to the utypes document (or to such a
> dumbing-down of data modelling, or whatever), *please* by all means
> speak up now.  I'll not be cross.  Promised.  You'll be saving me a
> lot of work.
>
> Finally, of course, if you think only parts of what I've tried are
> dead wrong, you're of course welcome to complain (or even fix), too.
>
> Cheers,
>
>            Markus
>
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-- 

---- Laurent MICHEL              Tel  (33 0) 3 68 85 24 37
      Observatoire de Strasbourg  Fax  (33 0) 3 68 85 24 32
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