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 Email: ktn-at-star.le.ac.uk Leicester, UK LE1 7RH Web: http://www.astrogrid.orgReceived on 2007-10-03Z18:20:22attached mail follows:
Hi Francois, On Mon, 1 Oct 2007, Francois Ochsenbein wrote:
> I really cannot understand why TAP should require an information schema.
> On one hand, you propose a simple table access, which any data provider
> can easily implement. On the other hand, you insist to implement a complex
> set of tables describing potentially a single table. This looks out of
> scope to me -- are we defining a relational database implementation, or a
> table access protocol ???
The purpose of this exercise is to actually show some examples of what the IS view would look like so that we can discuss in more specific terms the pros and cons. Thus, your response and examples speak directly to that purpose. A related question is, if we are not including queries via information schema in TAP v1.0, why consider it as a way to describe our tables. If we use the "FORMAT=METADATA" approach to describing the tables in v1.0, then it might make it inconvenient to switch to the IS approach if/when we begin supporting IS-based querying. That is, clients that have been built to understand FORMAT=METADATA would have to be rewired/extended to understand the IS-based description. *If* an IS-based description is just as straight-forward to support to begin with, it *may* make sense begin supporting the IS-based description right away for a smoother transition to a v1.1. This prototyping will help illuminate this hypothesis. I've formed a few opinions on these questions myself as a result of putting the example together, but I want to give people a chance to react a bit first before I share them. cheers, Ray