Community feedback re TAP metadata

[Patrick Dowler]

On Wednesday 07 March 2007 08:07, Doug Tody wrote:
> I do think we should distinguish between service metadata and dataset
> metadata.  Also; didn't we already discuss this issue in telecon #1,
> and agree that querying table metadata is a function of the TAP interface,
> not the registry?

It came up as an issue in meeting #1, and FO posted some materials later on, 
but we did not come to a decision on whether metadata would be TAP-specific 
or simply VOResource(s). 

Given the VOSI work, it seems pretty clear that the minimum effort for service 
metadata is to implement VOSI and return a VOResource for the service and it 
would be a shame to add a redundant TAP-specific service metadata mechanism,

As KA has reminded us, VOResource includes the capability to describe 
tables/datasets in some detail. I can't recall off hand if a service can 
have "child" tables/datasets. The "service for" does not (at least within UIs 
for creating registry entries) allow a single service to be the service for 
multiple dataset resources... but in any case, client software that access 
TAP services will already have to understand VOResource for the service 
metadata, so it again seems a shame to start thinking about other formats for 
table metadata. 

As for table metadata itself being tabular, yeah that's probably true, but 
that's just another way of saying that one element type in the VOResource 
schema could be used for every table. I don't see it as a compelling reason 
to actually use a tabular format. Specifically, a table is just a way to look 
at a list of things where all the things have more or less the same structure 
(in this case list of some subtype of VOResource). We gain nothing by 
flattening that into a table.

bright and early tomorrow AM!!

-- 

Patrick Dowler
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