TAP WD 1.0 par 1.3: broken equivalence
Alberto Micol
amicol.ivoa at googlemail.com
Fri Jul 10 10:22:03 PDT 2009
There are two examples of URLs for an "equivalent" query;
the first one uses ADQL and the second one PQL.
The problem is twofold:
1.- who will understand the PQL range syntax used in that example
(WHERE=r,10/16) ?
It should be mentioned where to find the definition of such a range
syntax.
2.- r,10/16 is _not_ equivalent to m.r>10 and m.r<16
because 10/16 specifies a closed interval (10,16 inclusive) as opposed
to the open one (10,16 excluded).
(I note here that given that those are magnitudes, hence floating
point numbers, there
is no exact way to formulate such m.r>10 and m.r<16 non-inclusive
interval
constraint using that range construct.)
PS: Sorry, I understand I am too picky here, but a spec in my view
should be both clear and precise
in all its details.
PS2: Of course an easy fix would be to correct the ADQL example adding
the >= and <=
to the constraint... but that I'd consider a cheat! ;-)
Alberto
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