[Asis-l] Fwd: Standard XML schema for MARC 21

[Melissa Riesland]

--- "Rebecca S. Guenther" <rgue at loc.gov> wrote:
> Date: Wed, 5 Jun 2002 09:28:48 -0400 (EDT)
> 
> Library of Congress announces standard MARCXML
> schema
> 
> The Library of Congress Network Development and
> MARC Standards Office
> announces completion of a schema for MARC 21
> records in an XML structure
> for use in communicating MARC 21 records.  It
> is available from
> http: www.loc.gov/marcxml.   This schema was
> developed in collaboration
> with OCLC and RLG and reviewed by the National
> Library of Canada and the
> National Library of Medicine (NLM), after a
> survey of schemas in use in
> various projects.  Many schemas have taken the
> Aslim@ approach but all
> vary slightly.  This schema will be maintained
> by the Library of Congress
> as will software that enables lossless
> conversion to and from MARC 21
> records in the ISO 2709 structure.  As
> illustrated in the introductory
> information on the web site, the Library of
> Congress will develop and
> provide, downloadable from the MARCXML web
> site, tools for various
> transformations and for record validations.  A
> single schema serves all
> the five MARC 21 formats.
> 
> By collaboratively developing a communications
> schema, the Library of
> Congress encourages the standardization of MARC
> 21 exchange records in the
> XML environment, recognizing that  MARC 21
> records inside systems will
> continue to use different record
> configurations, tailored to the
> characteristics of the system.  Provision of
> the tools for transformations
> to and from other metadata approaches, such as
> Dublin Core and the
> Metadata Object Description Schema (MODS), will
> help to standardize
> derivative metadata records also.  (MODS is a
> new schema for a
> bibliographic element set that is a subset of
> MARC expressed in XML with
> language-based rather than numeric tags.)  The
> tools take the mappings
> between MARC and other metadata sets, that have
> been maintained on the
> MARC web site, to an operational level. 
> 
> One project interested in a standard, lossless
> MARCXML schema is the Open
> Archive Initiative (OAI) which found it
> necessary to draft a schema in the
> absence of an official one.  The Library of
> Congress worked with the OAI
> to provide a transformation from the original
> oai_marc schema to this one
> so the Initiative can take advantage of a
> schema that is maintained by the
> MARC 21 maintenance agency and in broad use. 
> The transformation is
> available from the MARCXML web site.
> 
> With the slim approach, schema-driven
> validation is only possible at the
> highest structural level.  The Network
> Development and MARC Standards
> Office will therefore maintain downloadable
> tag, subfield, and value
> validation software on the web site that will
> enable users to build
> validation programs for their needs.  Use of
> these standard validations
> represent another attempt to assure
> standardization of records to support
> effective record interchange.  
> 
> The Library has maintained two SGML DTDs (for
> Bibliographic-type and
> Authority-type records) since 1996, which take
> a different approach to the
> data elements in MARC B an approach that
> enables validation of data
> through the DTD itself but requires a very
> large DTD and DTD
> maintenance.  The Bibliographic-type DTD was
> converted to an XML DTD in
> 2000.  These DTDs have been effectively used by
> some agencies (including
> the Library of Congress), primarily for
> internal processes, therefore
> transformations between them and the new slim
> MARCXML schema are being
> provided.  Maintenance techniques and/or
> possible revision of the XML DTDs
> are under consideration. 
> 
> For questions or comments please email the
> Office at ndmso at loc.gov. 
>  
> Sally McCallum, Chief
> Network Development and MARC Standards Office
> Library of Congress, Washington DC, USA
> 
> 

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