datasets and registries

[Tony Linde]

<<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 >>

The registry will tell you the ONE resource that matches ivo://NASA/HST,
since this is a unique resource identifier (where NASA is the AuthorityID
and HST is the ResourceKey). The metadata returned for that resource will
tell you the URL of that web service. The standard methods of such a service
are yet to be agreed, but I would assume one is a doQuery(string AdqlQuery)
type of method.

Cheers,
Tony. 


-----Original Message-----
From: amicol at eso.org [mailto:amicol at eso.org] On Behalf Of Alberto Micol
Sent: 18 September 2003 18:56
To: Tony Linde
Cc: registry at ivoa.net; adec at stsci.edu
Subject: datasets and registries


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 ... 
-- 
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