[OAI-implementers] Aggregator question

Tim Brody tim@tim.brody.btinternet.co.uk
Thu, 5 Dec 2002 15:32:22 -0000

Celestial already does this:

Although perhaps not very well ... (but unless you have a pressing need to
implement this in java, perhaps time would be better spent improving my
existing code, if needed?)

The oai-perl libraries I wrote convert OAI 1.x oai_dc records into OAI 2.0
oai_dc records by changing the schema namespace/location etc, and changing
the XML tag names, e.g.:
creator => oai_dc:creator

A providence record is added to the about section by Celestial that provides
the date this conversion occurred (broken due to schema URLs changing
location ... :-( ).

The source OAI identifier is maintained. The reason being, from my point of
view, whether OAI 1.0, 1.1, or 2.0 is used makes no difference to the actual
data provided by the oai-perl libraries (transparently and silently

Note also Celestial harvests the Set structure of OAI 1.x repositories and
exposes these through the OAI 2.0 headers.

I currently use Celestial as a buffer between Citebase and the source
repositories - so if something screws up in Citebase it doesn't overload
arXiv.org etc.

All the best,

----- Original Message -----
From: "Young,Jeff" <jyoung@oclc.org>
To: <OAI-implementers@oaisrv.nsdl.cornell.edu>
Sent: Thursday, December 05, 2002 2:48 PM
Subject: [OAI-implementers] Aggregator question

> We plan to harvest a mixture of OAI-PMH v2.0, 1.1 and possibly 1.0
> repositories, aggregate the results, and provide OAI-PMH v2.0 access to
> new repository. To do this, it will be necessary to upgrade old oai_dc
> metadata records to the 2.0 schemaLocation
> (http://www.openarchives.org/OAI/2.0/oai_dc/
> http://www.openarchives.org/OAI/2.0/oai_dc.xsd).
> According to section 2 of the  "Guidelines for Aggregators, Caches and
> Proxies" (http://www.openarchives.org/OAI/2.0/guidelines-aggregator.htm)
> "Agents which re-export harvested records should do so with different
> identifiers unless the metadata is unaltered...." The question is, then,
> does the change to a new schemaLocation constitute an alteration of the
> metadata?
> While I'm at it, I'm tempted to normalize the presence of xml namespace
> prefixes. For example, some repositories use an implied namespace prefix,
> some use oai_dc:dc, some use oaidc:dc, etc. Would this kind of change
> constitute an alteration of the metadata?
> Thanks.
> Jeff
> ---
> Jeffrey A. Young
> Consulting Software Engineer
> Office of Research, Mail Code 710
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