datasets and registries

[Alberto Micol]

> I guess the simple solution is that if you want to do anything with a
> dataset within the VO then it first needs to be registered as a resource.
> No?
>
> Cheers,
> Tony.
>

I don't think so.
Especially given the fact that every day the Registry would have
to collect all the information relative to tons of new datasets that have been
produced during the night ...

Let's start from the following HST/WFPC2 observation (doesn't need to be HST):

 ivo://NASA/HST#U3814G01T

I hope that the registry will be able to tell me which services exist
that can recognise an ID that matches the  ivo://NASA/HST part (anything before the '#' sign, hence without the datasetID). ThenI will query them with the datasetID (U3814G01T).

I will probably be more specific and ask the registry which services among
those are able to give me a certain information.
For example, if I'm interested in metadata for a given ID, I will ask
(in SQL to clarify the concept, but does not need to be SQL of course):

  select serviceID

  from Registry

  where

       service_knows_ID = "ivo://NASA/HST"

   and service_type  = "interrogable_by_datasetID"

   and service_output = "METADATA"





But if I want to retrieve such dataset I will have to ask the registry
which service can do that for me, eg:


 select serviceID

 from Regisitry

 where

       service_knows_ID = "ivo://NASA/HST"

   and service_type  = "interrogable_by_datasetID"

   and service_output = "DATA"

The registry gives you the identifiers of the services that can be used
to do what a user needs. It will be up to the user to actually use that service.
Unless we build a portal that can bind services together, but that will
be at quite a different level. Let's start with the first things first.

Alberto

PS: This brings me back to the problem of having a dictionary for those terms
that I used within quotes in the above SQL statements ...

--
Alberto.Micol at eso.org                         Tel: +49 89 32006365
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