OAI coordination

[Gerard Lemson]

Hi Ray

> 2.  "root" element for VOResource metadata; that is, the child of the
>     <oai:metadata> element:
>
>     I recommend we use <VOResource>, for the following reasons:
>
....
>   *  one <Authority> record (see
>      http://nvo.ncsa.uiuc.edu/VO/schemas/vomdoc-v0.9/VORegistry-v0.2.html#element_Authority)
>      for each AuthorityID it creates records for.
>
>   *  at least one <Registry> record (see
>      http://nvo.ncsa.uiuc.edu/VO/schemas/vomdoc-v0.9/VORegistry-v0.2.html#element_Registry
>      that describes itself.  This record should include a listing of all
>      the AuthorityIDs it manages (i.e. that it has Authority records for)
>      using the <ManagedAuthority> element
>
> No two registries can claim to manage the same AuthorityID.  While this
> may not remain true in the future, for now, this is the way we track
> resource records back to their origin (as discussed by Alex).

Are these proposals, in whatever form they'll end up being adopted,
going to be formalized in the schema definitions as well ?
The current schema allows for any of the many (global) elements
(defined under <xs:schema>) to be used as the root element of a
valid document. As you say, this makes validating documents a much more
difficult job, especially if you use some source generator like JAXB or
Castor for which validation is almost a no-brainer.

I guess an alternative approach is to say that the current schemas are not
normative for valid documents sent to/from (registry) services, but that
separate schemas using the current ones are being created ?
Is that maybe the idea? I think this fits in nicely with a kind of
model (the core schemas) vs view (derived, document schemas) approach.

If not, if the current schemas are defining valid VO documents as well,
the current design methodology, which heavily relies on using element
"ref"-s with their required global elements is problematic.
If you're interested I've created an alternative "port" of your schema's
that uses element "type" definitions. It carries the same semantics.
It validates XML documents that are almost identical to those validated
by the current schemas, but has currently only two global elements,
VODescription and VOResource. They do moreover have a lower "impedance
mismatch" with obvious object-data modeling approaches.

Cheers
Gerard