[OAI-implementers] Qualified Dublin Core

Young,Jeff jyoung at oclc.org
Thu Aug 12 09:48:28 EDT 2004

Speaking only for myself as a service provider, I doubt that I will be
interested in a generic container of "things". I simply don't have the time
or patience to figure out what's what in a blob of data. Including a
"schema" attribute and "element" element might help, but the investigation
still sounds difficult. In addition, my sense is that taking the easy route
and blindly pulling DC and DCQ elements from the blob (or elements from any
other namespace) will produce a meaningless jumble 9 times out of 10. I
could be wrong, though.


> -----Original Message-----
> From: Stephen Crawley [mailto:crawley at dstc.edu.au]
> Sent: Wednesday, August 11, 2004 10:36 PM
> To: oai-implementers at oaisrv.nsdl.cornell.edu; crawley at piglet.dstc.edu.au
> Subject: Re: [OAI-implementers] Qualified Dublin Core
> Folks,
> A canonical container XSD for qualified DC would be useful, but it
> doesn't really solve the problem, IMO.
> Why?  Because many (most) DC-based metadata collections use elements and/
> or refinements that are not in DCQ.  These can be extensions mandated
> by some other standard (e.g. AGLS, EdNA, etc) or site-specific
> extensions. So, while oai schemas for exchanging DCQ, AGLS, EdNA, etc
> would be useful, the larger problem is how to exchange metadata with an
> arbitrary metadata schema ... without defining yet another XML schema
> to transport the records.
> The solution (as we see it) is to use XSD that is *insensitive* to the
> metadata's schema.  In the simple model, the OAI repository assembles
> XML records containing whatever elements it is prepared to publish. The
> OAI client would then sort through the supplied elements, throwing away
> any that it doesn't want / understand, and massaging others as required.
> Then the client validates the filtered records against its own metadata
> schema before it decides what to do with them.
> The problem of elements meaning different things in different schemas
> is a bit tricky.  However, you can get some traction if each record's
> metadata schema identifier is included in the record.
> For info: I've attached the XSD schema that DSTC's MetaSuite system uses
> for passing metadata records between Broker instances over OAI.  The XSD
> is not suitable for general use because it contains a lot of MetaSuite
> specific admin fields.  However, it illustrates the approach. The key
> bits of the XML schema are the "schema" attribute and the "element"
> element.  The latter represents the element's prefix + name + refinement
> as the "id" attribute.
> If anyone is interested in developing an OAI spec for schema-independent
> metadata interchange, please drop me a line.
> -- Steve
> +----------------------------------+--------------------------------------
> --
> | Stephen Crawley                  | MetaSuite Project Leader
> | Level 7, GP South Building (78)  | Distributed Systems Technology CRC
> | Staff House Road                 | Tel   : +61 7 3365 4310
> | The University of Queensland     | Fax   : +61 7 3365 4311
> | Queensland 4072                  | Email : crawley at dstc.edu.au
> | Australia                        | WWW   : http://www.dstc.edu.au
> |                                  | DSTC is the Australian W3C Office
> +----------------------------------+--------------------------------------
> --

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