TAP usage in practice - we have a small problem.

[Markus Demleitner]

Hi Walter,

On Fri, May 19, 2017 at 12:09:40AM -0700, Walter Landry wrote:
> Markus Demleitner <msdemlei at ari.uni-heidelberg.de> wrote:
> > http://wiki.ivoa.net/twiki/bin/view/IVOA/HowToEnableTableDiscovery.
> > 
> > It'd be great if the major TAP service operators could have a look
> > and ideally implement these steps;
> 
> It looks like the recommendation is to duplicate the /tables endpoint.

Well, historically, the /tables endpoint duplicated the VODataService
tableset, but yes, the same information is disseminated in two distinct
ways.  If your SCS services had tables endpoints (which, if you read
VOSI with sufficient zeal, you could say they should), their contents
would be exactly what should end up in the registry record.

> I do not have one of those, and it would be some effort to generate
> it.  It would be easy to add a tableset that has a table name, but no
> columns.  But I have a feeling that would be frowned upon.

For current TOPCAT, that would be enough (as it only evaluates table
metadata at this point), so I'd encourage you to put it in at least
as a stopgap measure.  

Other clients support column discovery (WIRR, for instance, lets you
look for services with columns having a certain UCD, and Aladin has,
as we've seen, functionality like "datasets with proper motions") --
for those, providing columns would be great, so on the long run,
that'd sure be a good thing, too.

Thanks,

           Markus