SIA Evolution Proposal

[Clive Page]

On Fri, 16 Apr 2004, Alberto Micol wrote:

> >you could model your data as:
> >
> >results -- Filter -- Observation
> >
> >instead of
> >
> >results -- Observation -- Filter

> It looks to me that your model is indeed imposing the data provider view
> to the users.

I'm inclined to agree with Alberto here: of course the famous rules of
Codd and Date tell us never to duplicate data.  But here we have two
observations (which are pretty natural units in the astronomical world)
which just happen to have the same filter setting.  I don't see it as
terribly wasteful to have the filter values specified twice, once within
each observation chunk, even though that duplicates the information,
wastes file space, etc.  When you (or your software) access the data, I
would have thought it better to have the filter information in an expected
place than to have to root around in the structure for it.


-- 
Clive Page
Dept of Physics & Astronomy,
University of Leicester,
Leicester, LE1 7RH,  U.K.