I'm still confused about all this stuff too, but I've often see the
oai_dc format (for OAI/PMH I think?) used as a 'standard' way to expose
simple DC attributes.
One thing I was confused about was whether the oai_dc format _required_
the use of the "old style" DC uri's, or also allowed the use of the
DCterms URIs? Anyone know? I kind of think it actually requires the
old-style DC uri's, as it was written before "dcterms".
At least it is one standardized way to expose the old basic DC elements,
with a specific XML schema.
Jonathan
Riley, Jenn wrote:
Hi MJ,
- for that matter, is there a good example of how to "properly"
serialize DCTERMS for eg. a converted MARC/MODS record in XML (or
RDF/XML)? I see, eg. <http://dublincore.org/documents/dcq-rdf-xml/>
which has been replaced by <http://dublincore.org/documents/dc-rdf/>
but I'm not sure if the latter obviates the former entirely? Also, the
examples at the bottom of the latter don't show, eg. repeated elements
or DCMES elements. Do we abandon http://purl.org/dc/elements/1.1/
entirely?
This has always been ridiculously confusing! Here's my understanding (though
anyone else, please chime in and correct me if I've misunderstood):
- With the maturation of the DCMI Abstract Model
<http://dublincore.org/documents/abstract-model/>, new bindings were needed to
express features of the model not obvious in the old RDF, XML, and XHTML bindings.
- For RDF, <http://dublincore.org/documents/dc-rdf/> is stable and fully intended to
replace <http://dublincore.org/documents/dcq-rdf-xml/>.
- For XML (the non-RDF sort), the most current document is
<http://dublincore.org/documents/dc-ds-xml/>, though note its status is still (after 18
months) only a proposed recommendation. This document itself replaces a transition document
<http://dublincore.org/documents/2006/05/29/dc-xml/> from 2006 that never got beyond
Working Draft status. To get a stable XML binding, you have to go all the way back to 2003
<http://dublincore.org/documents/dc-xml-guidelines/index.shtml>, a binding which predates
much of the current DCMI Abstract Model.
- Many found the 2003 XML binding unsatisfactory in that it prescribed the format for individual dc and dcterms
properties, but not a full XML format - that is, there was no DC-sanctioned XML root element for a qualified DC
"record". (This gets at the very heart of the difference in perspective between RDF and XML, properties
and elements, etc., I think, but I digress...) The folks I'm aware of that developed workarounds for this were
those sharing QDC over OAI-PMH. I find the UIUC OAI registry <http://oai.grainger.uiuc.edu/registry/>
helpful for investigations of this sort. A quick glance at their report on Distinct Metadata Schemas used in
OAI-PMH data providers <http://oai.grainger.uiuc.edu/registry/ListSchemas.asp> seems to suggest that
CONTENTdm uses this schema for QDC <http://epubs.cclrc.ac.uk/xsd/qdc.xsd> and DSpace uses this one
<http://dublincore.org/schemas/xmls/qdc/2006/01/06/dcterms.xsd>. The latter doesn't actually define a root
element either, but since here!
a!
t least the QDC is inside the wrappers the OAI-PMH response requires it's
well-formed. What someone does with that once they get it and unpack it, I
don't know, since without a container it won't be well-formed XML. The former
goes through several levels of importing other things and eventually ends up
importing from an .xsd on the Dublin Core site, but they define a root element
themselves along the way. (I think.)
- So what does one do? I guess it depends on who your target consumers of this data
are. If you're looking to work with more traditional library environments, perhaps
those that are using CONTENTdm, etc. the legacy hack-ish format might be the best.
(I'm part of an initiative to revitalize the Sheet Music Consortium
<http://digital.library.ucla.edu/sheetmusic/> and lots of our potential
contributors are CONTENTdm users, so I think this is the direction I'm going to take
that project.) But if you're wanting to talk to DCMI-style folks, the dc-ds-xml, or
more likely the dc-rdf option seems more attractive. I'm afraid I'm not much help
with the implementation details of dc-rdf, though. One of the DC mailing list would
be, though, I suspect. There are a lot of active members there.
Ick, huh? :-)
Jenn
========================
Jenn Riley
Metadata Librarian
Digital Library Program
Indiana University - Bloomington
Wells Library W501
(812) 856-5759
www.dlib.indiana.edu
Inquiring Librarian blog: www.inquiringlibrarian.blogspot.com
