Re: Community feedback re TAP metadata

Hi Doug,

> Database and Table metadata as see in TAP on the other hand, is not
> service metadata. It is tabular data and is very similar to data
> returned from a data table or catalog, the only difference being the
> logical content of the "table" being queried. It is advantageous
> to use a similar mechanism to access both table data and metadata,
> hence use of VOTable is reasonable here.
>
> Am I missing something or does the discussion below completely miss
> this point?

The registry resource specification does *not* only cover "service" metadata - it also deals with "table" metadata, if you wish to draw a distinction between the two.

Database and table metadata can (and in our opinion should) be expressed in the registry entry/ies describing a data service; in other words, everything that needs to be known about the service and its data should be available in the registry, including table metadata. Appropriate VOResource types already exist for this and are undergoing further development in the registry group - we should contribute to that process if we find the current specification inadequate.

My impression from our previous discussions was that the mandatory getMetadata method(s) in TAP would return VOTable (only). We believe that the mandatory method(s) should return the appropriate VOResource type(s) for describing tabular data, with return in VOTable format as an optional or mandatory extra.   

Cheers,
Kona

-- 
Kona Andrews        kea-at-roe.ac.uk
AstroGrid Project   http://www.astrogrid.org
IfA, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ