resuming progress on TAP

[Keith Noddle]

> One way to approach this would be to follow the same strategy that the VOQL 
> group did when separating ADQL and TAP: we could specify the "DAL 
> parameter-based query language" in a separate document that goes through the 
> standards process. It would be usable (referenced) by all DAL services. The 
> TAP spec would refer to the ADQL spec as a required language and allow for 
> use of other languages.
> 
> Mechanically, the TAP service metadata would have to describe which query 
> languages and versions are supported, but we have to do that in any case.
I agree. I like that it frees up the option to relatively easily add 
other optional querying capabilities (XQuery for object databases/other 
XML data resources, maybe?) at some point in the future.

> This would decouple the TAP and param-query specs, allowing each to move 
> forward at whatever pace can be sustained. It would result in a single TAP 
> specification and there would be no particular need to make a new version 
> once param is complete. It would also benefit other DAL service 
> specifications to have a common spec for param query that can be referenced  
> rather than just copying it from one service spec to the next.
This is an improvement on my suggestion, thank you for making it. 
Working towards a common spec for param based querying makes a lot of 
sense from the perspective of all the so-called "Simple" access 
protocols, laying the groundwork for future standards

You have articulated two very powerful concepts here and I think this 
approach has much merit - more than my original, certainly. It would 
help to hear comments from other interested parties. Right now I am 
concerned that the debate is crystallised around the same old names - an 
injection of fresh ideas would be most welcome.

Keith.

-- 
Keith Noddle                    Phone:  +44 (0)116 223 1894
AstroGrid Project manager       Fax:    +44 (0)116 252 3311
Dept of Physics & Astronomy     Mobile: +44 (0)7721 926 461
University of Leicester         Skype:  keithnoddle
Leicester                       Email:  ktn at star.le.ac.uk
LE1 7RH, UK                     Web:    http://www.astrogrid.org