rplante at poplar.ncsa.uiuc.edu
Fri Feb 6 03:33:02 PST 2009
On Thu, 5 Feb 2009, Ray Plante wrote:
> (0) To create an integrated spec where ADQL is mandatory and parameterized
> query is optional. This was the basic agreement from the IVOA meetings, yes?
> On Thu, 5 Feb 2009, Keith Noddle wrote:
>> (1) We adhere to the decisions of the IVOA and define a TAP standard that
>> includes only asynchronous ADQL-based querying. We follow that quickly with
>> the next revision of the TAP document that includes optional parametrised
>> querying. Separating them out will allow progress on each to be made.
Might I suggest that it is your option 1 that departs from the
most recent decisions of the IVOA, decisions that led to the formation of
the tiger team and version 0.3*? Preserving the efforts of that group was
at the heart of Bob's comments before Christmas and which I was hoping we
could give a honest go at.
The motivation behind the integrated approach was to ensure an integrated
underlying architecture. In fact, this brings up two issues I would put
on a list of "issues to talk about" list:
1. How should the architectural approach be framed? In the previous
revisions, we saw a tension between two reasonable approaches that
had been developed in independently coming together in TAP:
o a REST-based approach (originating from GWS)
o the so-called DAL2 approach (originating from DAL)
Is there an integrated approach that does not reject the advantages
and progress made to date of either one?
2. How should should the relationship between Param-Query and ADQL be
presented? Should both be presented as parallel, fundamental
interfaces (based on an integrated architecture) or should
Param-Query be defined as a layer on top of ADQL?
The two most versions of the TAP document, I think, favored
different sides of this question. In particular, in one version,
parts of the Param-Query interface were moved to appendices.
Splitting the spec into the two steps would appear to favor (a) the REST
architectural approach and (b) the choice of layering Param-Query on top
Nevertheless, your suggestion is out there now for consideration,
and seeing the outlines is *very* helpful. It might also be helpful to
put out an outline that shows the difference between 0.30 and 0.31.
Most importantly, though, I would like to hear people's reactions to the
two issues I listed above. If we can gain some consensus on these issues,
then we know whether to continue with an integrated approach (and benefit
from progress in the fal), to split into a 2-step approach, or perhaps
some other option.
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