Extensions on the registry

[KevinBenson]

I just thought it might be good to start the specific topic of extensions as
a separate Thread.  I must say I do sort of like the idea Matthew has down
(at the bottom) where if you wanted to find out if there is a supported
Schema or namespace, it might help try to solve one of the questions below..

I do agree with Tony that it is nice if we are able to store extensions to
the Resource schema.  Even if we might not be able to query on it.

But is there general agreement to all of this in the IVOA?  I don't know.

So lets kick off with a couple of questions on this thread.
Does everybody agree that we should be able to on Full Registries store all
Resources including extension Resources?
Would it be okay if certain Full Registries would not be able to query on
them and possibly never query on them (them being the extension part of the
schema's)?  Is this where we could maybe use the getSupportedSchema.  So
using Matthew's idea below: An app who know they are not part of the IVOA
standard schemas could ask the registry if there schema is supported by a
particular registry.   My take is Supported means queryable.

Cheers,
Kevin

FYI.
The way Astrogrid would work on an extension would be that you would be able
to store it and you would be able to query for the Resource record if it was
a query just on known namespaces hence IVOA standard namespace schemas.  But
once an app/user tried to query on an particular element that was of that
extension, it would fail because the namespace is not known to the query
mechanism.  The good thing is you simply just add the "declare namespace..."
on a particular config property to have it work.

-----Original Message-----
From: owner-registry at eso.org [mailto:owner-registry at eso.org]On Behalf Of
Matthew J. Graham
Sent: 11 April 2005 16:30
To: Tony Linde
Cc: registry at ivoa.net; 'Roy Williams'
Subject: Re: RofR


Hi,

On Apr 11, 2005, at 6:31 AM, Tony Linde wrote:

>
> If a registry supports a query interface, it is a full registry - it
> must
> contain all resource records (therefore must harvest from other
> registries
> in order to do so).

I disagree. A domain specific registry, e.g. one that contains
resources of relevance to the GRB community, can support the query
interface because GRB folks want to be able to search it but does not
need to hold all resource records which the GRB people have no interest
in and would be extra admin for the registry maintainer.

The options for a registry are really:
- is it a publishing registry (I can harvest the records it maintains)
- is it a "full" registry (it contains most records which I can access)

The availability of a search interface has nothing to do with the size
of the contents.

I also think we need to drop this idea of a full registry because
supporting every variant schema that every astronomer comes up is
unrealistic (and this has nothing to do with relational/native XML
implementation), e.g. is Astrogrid intending to support the horrible
hack schema that identifies records from the Penge Local Astronomy
Youth Club?  I think we should have an extra piece of metadata on the
Registry record which lists the schemata that the registry supports and
this should also have one method on the Registry Interface at least:
getSupportedSchema() - may also isSupported(XMLSchema mySchema)?

	Cheers,

	Matthew