separating TAP and query languages

Roy Williams roy at cacr.caltech.edu
Sun Feb 22 17:55:35 PST 2009


Pat
I like your idea of the LANG keyword, it allows creative scope for 
creating the kind of services that will most benefit the astronomical 
community. It immediately made me think of LANG=MULTICONE for the kind 
of "simple inclusive crossmatch" with a small, simple, standard, 
something that could be running in multiple places by April.

But when I started reading the document below, it says that ADQL is 
"mandatory", VOSI compliance is "mandatory", metadata queries are 
"mandatory", RUNID is "mandatory", and so on and so on. Years of time 
and effort to expend on all these things before even starting with the 
"optional" parts of TAP, i.e. multicone. You have made TAP a monolith. 
However I am not seeing the software toolkit to let me build a compliant 
TAP service from my database, and I am not seeing this being built 
anywhere(?).

I am associated with a small sky survey which is ready to publish its 
results "in VO form". What would you recommend for the small data 
provider in the ~1 year timeframe? Wait for the TAP toolkit to be in 
beta? Cone search? Skynode? Casjobs on windows? Upload to Vizier and 
hope they can make a full TAP?

Roy



Patrick Dowler wrote:
> I took a quick stab at separating the param query language from the TAP spec 
> and I think the result is quite clean and encouraging. I tried with normative 
> text and examples to show how PQL would be used in TAP. There are some loose 
> ends remaining but it is workable and gives more or less the same actual 
> interface that TAP 0.31 described. 
>
> The main change is that REQUEST no longer distinguishes the query language: 
> there is one value for doing a query (imaginatively named "doQuery") and the 
> 3 VOSI-related request values. This remains consistent with DAL2. If the 
> value of REQUEST=doQuery, then the caller must also specify LANG, which is 
> where the language is set (e.g. LANG=ADQL as before, but now also LANG=PQL, 
> with language version optionally embedded in the LANG value). All remaining 
> parameters depend on the value of LANG.
>
> Draft documents are posted on
>
> http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/TableAccess
>
>   

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