IVOA Identifiers Working Draft

[Ray Plante]

On Fri, 12 Sep 2003, Tony Linde wrote:
> > There is also the separate but related question I posed:  Can an IVOA 
> > identifier exist for a resource that is not registered 
> > anywhere?  If so, 
> > what are the constraints (i.e. "as > long as ...")?
> 
> Not really since there is no way the registry can know not to create a
> ResourceId that conflicts with it.

ResourceKeys are created by the owner of the AuthorityID.  If the owner is 
an organization, and not strictly the registry, then in the registration 
process, the registry must receive the ResourceKey from the 
registering organization.  That is, the registry should *not*, in general, 
choose the ResourceKey for the registrant.  The registry can check its 
uniqueness against the ResourceIDs it knows about; however, it is 
ultimately the responsibility of the organization to ensure that it does 
not conflict with IDs that have not be registered.  

Is that good enough?

> > Associating Sa.CXO with a data collection's ShortName is not 
> > a good idea, 
> > because there is no guarantee that it is unique and will consistantly 
> > refer to the same data collection.  This is exactly the role of an 
> > identifier: to be a unique reference.  
> 
> It isn't unique but could be used to get a list of data collections which,
> if it is >1 in length would need human intervention.
> 
> Not ideal but where is the list of associations between Sa.CXO and the
> unique identifier held?

I think the point is that Sa.CXO/2000 is a unique identifier.  At the 
moment, the ADEC group is planning to host a service that resolves such an 
identifier into a URL (or URLs).  

cheers,
Ray