vo-dml for cube

[Laurino, Omar]

Francois,

On Tue, Dec 15, 2015 at 11:55 AM, François Bonnarel <
francois.bonnarel at astro.unistra.fr> wrote:

> PS : I am not considering here any kind of serialisation of these VO-DML
> decscriptions (Object relational maaping, VOTABLE Mapping,
> specific-stc2-xml-schema xml  documents, json, etc... ). this is another
> story but the initial VO-DML description will constraint the solution.


I mostly agree. However, one of the benefits of VO-DML is to have a
language that can easily be mapped to a variety of contexts, including OO
languages and relational databases, and so ORM. If variable length arrays
were impossible (or very hard) to treat in ORM, then they should be left
off the language, because they would be impossible (or very hard) to treat
in a fundamental set of implementations.

But yes, the implementation details of how to map VO-DML model instances to
a serialization is a different topic. So for instance, a model might call
for a great number of Object Type instances, but specific serialization or
representation formats might allow more efficiency, whether we are talking
about Java objects or SQL tables, or FITS. An image might have, in
principle, an Object Type representation for each pixel in an image, but a
FITS representation might factor out all the common metadata into a single
representation for all the pixel in the image. I say in principle because I
am not sure I can take a side in the modeling part per se, so I don't have
an opinion on whether a pixel should be an Object Type or a Data Type, in
this example.

Omar.


-- 
Omar Laurino
Smithsonian Astrophysical Observatory
Harvard-Smithsonian Center for Astrophysics
100 Acorn Park Dr. R-377 MS-81
02140 Cambridge, MA
(617) 495-7227
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ivoa.net/pipermail/dm/attachments/20151215/8854a8ab/attachment.html>