MARC and XMLELAG 17-19 April 2002, Rome

Mette Båstrup mbl@portia.dkwww.portia.dk

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Overview

IntroductionWhat has been done and what to achieveXML Schema specificationsGaining consensus

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Why XML for MARC?

Widespread standard technologies http://www.w3c.org

XML (data structure)XSD schemas for specification replacing DTD and XDR schemasXSL (presentation and customised validation)

Standard tools available (IBM, Microsoft, XML Spy)

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What has been done in this area?Library of Congress MARC DTD

ftp://ftp.loc.gov/pub/xmldtd/mrcbfile.dtd

Open Archive Initiative (OAI) MARC XML http://www.openarchives.org/OAI/oai_marc.xsd

VisualCat XDR and XSD schemas

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Related technologies

Dublin Core RDF XML http://dublincore.org/documents/2001/11/28/dcmes-xml/ http://www.portia.dk/pubs/RDF/DcRdfBasic20020321a.xsd

MODS from Library of Congress http://www.loc.gov/standards/mods/

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MARC validation rules

Syntax rulesFormat rules e.g. 5 digit subfieldList of valid codesISBN validation

Context dependent rulesIf subfield a is 10 then subfield b is 20

Sequences of subfields in a field e.g. a e a e a e b k l

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Problems when going to XML

MARC records are not self identifyingTag names (characters not allowed as an XML element name) Character sets No formal specification of MARC recordsUser specified fields in the headerNon valid MARC records

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Goals for XML Schemas

Self identifying MARC recordsSpecifying rules:

General MARC 2709 rulesRules for the different MARC flavoursRules for a specific application

Use built-in schema validationExtend schemas with application specific information

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The general MARC Schema

Specifications at: http://www.portia.dk/pubs/VisualCat/Specs/MarcXml/MarcTemplate2.xsd Specifying general information:

MARC record incl. MARC headerMARC fieldMARC subfield

No specification of specific fields e.g. Field 001, Field 002 etc.

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General MARC schema excerpt<xs:complexType name="marcType" abstract="true">

<xs:sequence><xs:element name="MarcLeader"

type="mc:marcleaderType"/></xs:sequence>

</xs:complexType><xs:complexType name="varfieldType" abstract="true">

<xs:attribute name="i1" type="xs:string" use="optional"/><xs:attribute name="i2" type="xs:string" use="optional"/>

</xs:complexType>

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The specific MARC flavour schema

Specification at: http://www.portia.dk/pubs/VisualCat/Specs/MarcXml/danMarc2Template2.xsd Specifying record for a given MARC flavour i.e MARC21, UNIMARC etc.Specifying validation rulesRedefining the schema for a given situation e.g. cataloguing music

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Specific MARC flavour schema excerpt I<xs:element name="Field-100">

<xs:annotation><xs:documentation><DisplayName

xml:lang="da">Personnavn</DisplayName> <ElementDesc Location="http://www..." MarcTag="100"/></xs:documentation></xs:annotation><xs:complexType><xs:complexContent>

<xs:extension base="mc:varfieldType"><xs:sequence>

<xs:element ref="dm2:Subfield-100-a" minOccurs="0" maxOccurs="1"/>

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Specific MARC flavour schema excerpt II<xs:extension base="mc:marcType">

<xs:sequence><xs:element ref="dm2:Field-100"/><xs:element ref="dm2:Field-245"/>

</xs:sequence><xs:attribute name="MarcRecordSyntax" use="required">

<xs:simpleType><xs:restriction

base="mc:marcrecordsyntaxType"><xs:enumeration value="DANMARC"/>

</xs:restriction></xs:simpleType>

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What has been gained?

Platform independent specification of MARC formatCan be used directly in an application with freely available standard toolsCan be read and maintained by non techniciansTo be determined: Schema for exchange of MARC records based on OAI MARC/XML