On February 24, 2003 12:05, Ed Shaya wrote:
> I just want to reiterate that I think VOQL should be a means for the
>
> astronomer to clearly specify what astronomical knowledge he/she wants.
> It should not require the astronomer to know how data is arranged at
> each of the data centers, nor all of the steps required.
This point cannot be over-emphasized. Storage data management by services/institutions will vary alot and it must remain a hidden implementation detail - with plenty of freedom on the part of a service to implement in a suitable fashion.
>
> The astronomer thinks "I am interested in objects with such and such
> properties" and VOQL should allow a description of these constraints,
With the ention of the word "constraints", I'll jump in here:
Our work at CADC and some of my past work has been in the area of constraint systems. The great advantage of constraint-based systems is that they do not, in the general case, specify a query system per se. The same constraint system can be applied as a query, a processing (typically filtering) step, a theorem-prover, etc.
Since VOQL is still young, I suggest that instead of inventing a "query language" we will be better servced by a constraint toolkit. The advantages are many:
Although I don't go crazy for this sort of thing:
My 2c (although I guess Canadians should up that to 3c),
-- Patrick Dowler Tel/Tél: (250) 363-6914 | Fax: (250) 363-0045 Canadian Astronomy Data Centre | Centre canadien de donnees astronomiques National Research Council Canada | Conseil national de recherches Canada Government of Canada | Gouvernement du Canada 5071 West Saanich Road | 5071, chemin West Saanich Victoria, BC | Victoria (C.-B.)Received on 2003-02-24Z22:04:07