Extensions on the registry

[Guy Rixon]

Tony,

for your definition of "query", quoted below, I think query can and should be
mandatory for all registries even in the presence of extensions. However, I'd
make one condition on this: the extended resource-document MUST be checkable
against its schema. That means that the document MUST have a schema
in the first place, the schema MUST be published and the schema location MUST
be written in the resource document itself. By "published", I mean that the
schema is downloadable from some fixed URL (to go in the schemaLocation
attibute) and that the namespace is never reused to publish a different
schema; usual health rules for public XML.

Registries _do_ present data as XHTML; but I agree that this is no part of the
IVOA spec.

Cheers,
Guy

On Wed, 13 Apr 2005, Tony Linde wrote:

> > If "query" means "extract metadata from resource documents,
> > transform and present to user as XHTML", then clearly a given
> > registry can't do this properly for unknown extensions.
> > (Nominating XSLT stylesheets in processing instructions might help.)
>
> No - registry does not 'present' the data in any way.
>
> > If "query" means "return the resource document matching a
> > given IVOID" then that works with or without extensions.
>
> Yes.
>
> > If "query" means "return XML fragments extracted from
> > resource documents according to some query language such as
> > XQuery or ADQL" then it's less clear.
>
> No - any such function would need to be extra functionality offered by a
> registry (e.g. by offering an XQuery interface).
>
> Cheers,
> Tony.
>
> > -----Original Message-----
> > From: owner-registry at eso.org [mailto:owner-registry at eso.org]
> > On Behalf Of Guy Rixon
> > Sent: 13 April 2005 09:53
> > To: Ray Plante
> > Cc: registry at ivoa.net
> > Subject: Re: Extensions on the registry
> >
> > On Tue, 12 Apr 2005, Ray Plante wrote:
> >
> > > On Tue, 12 Apr 2005, KevinBenson wrote:
> > > > Does everybody agree that we should be able to on Full Registries
> > > > store all Resources including extension Resources?
> > >
> > > My current take, personally, is that Full registries *should* store
> > > all records, even though they contain extensions; however, I'm not
> > > sure I would go as far as "must", since this has potentially
> > > substantial implementation issues.  The next question is, what does
> > > this do to the meaning of "Full"?  If a registry does not include
> > > extensions, is it allowed to declare itself full, or can we
> > live with a fuzzier definition?
> > >
> > > > 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)?
> > >
> > > Yes.
> >
> > Doesn't it depend on what you mean by query?
> >
> > If "query" means "extract metadata from resource documents,
> > transform and present to user as XHTML", then clearly a given
> > registry can't do this properly for unknown extensions.
> > (Nominating XSLT stylesheets in processing instructions might help.)
> >
> > If "query" means "return the resource document matching a
> > given IVOID" then that works with or without extensions.
> >
> > If "query" means "return XML fragments extracted from
> > resource documents according to some query language such as
> > XQuery or ADQL" then it's less clear.
> > My guess is that an XQuery or XPath query would work even on
> > resources-with-extensions and that an ADQL/SQL query might
> > have problems.
> >
> > I think we should mandate the
> > return-entire-document-matching-IVOID query for all
> > registries even in the presence of extended documents. (I'd
> > also prefer XQuery over ADQL for the structured query, but
> > that's a separate issue.)
> >
> > Cheers,
> > Guy
> >
> > Guy Rixon 				        gtr at ast.cam.ac.uk
> > Institute of Astronomy   	                Tel: +44-1223-337542
> > Madingley Road, Cambridge, UK, CB3 0HA		Fax:
> > +44-1223-337523
> >
>

Guy Rixon 				        gtr at ast.cam.ac.uk
Institute of Astronomy   	                Tel: +44-1223-337542
Madingley Road, Cambridge, UK, CB3 0HA		Fax: +44-1223-337523