XML

1
XML Library Applications

• ELAG 2001
• Poul Henrik Jørgensen, phj_at_dbc.dk
• Danish Bibliographic Centre, www.dbc.dk

2
Objective

• To identify family of relevant XML standards
• To describe existing use of XML standards within
  important Bibliographic IT standards
• To identify future development of Bibliographic
  IT standards based on XML standards
• Not an introductory course in the XML standards
  themselves!

3
Content

• XML Standards Overview
• Major benefits of XML
• MARC formats and XML
• Z39.50 and XML formats
• Interlibrary Loan transactions in XML
• NISO Circulation Interchange Protocol and XML
• ZML Z39.50 as XML Protocol
• RDF Semantic Web and Metadata

4
XML Standards Overview

• Family of related standards from W3C
• XML Representation of hierarchical data
• XML Schema Specification of XML structure
• XHTML Presentation/display of data
• DOM Internal representation of XML
• XSLT/XPath Transformation of XML
• RDF Relationships between Objects and Classes

5
Major benefits of XML

• Easy to understand by humans as well as by
  computers
• Supported by all mainstream IT vendors
• Handles hierarchical information well
• Can be edited by simple tools
• Many IT people knows XML

6
OAI MARC XML Schema

• Developed for Open Archives Initiative
• Similar to limited ISO 2709 structure
• Single Field element type containing single
  Subfield element type
• Field- and Subfield instances identified by
  attribute values
• Suitable for exchange and conversions
• http//www.openarchives.org/OAI/oai_marc.xsd

7
MARC XML Schemas

• Developed for VisualCat and ONE-2 project
• Similar to LC MARC DTD
• Each possible combination of Field and Subfield
  specified as separate XML Element Types
• danMARC2 164 MARC Fields and 1189 Subfields
• Suitable for automatic syntax validation
• Schemas for MARC21 (British Library), UNIMARC
  (Italian SBN) and danMARC2 (DBC)

8
VisualCat MARC21 Schema
9
Z39.50 and XML formats

• CompSpec option may specify Record Syntax,
  Schema, and Element Specification
• recordSyntax identifies format, e.g. XML (OID
  1.2.840.10003.5.109.10)
• Schema identifies structure e.g. Holdings
  (OID1.2.840.10003.13.7.1)
• elementSpec identifies subset, e.g. Level B-1
  Minimal Bibliographic Level Holdings (ESNB1)

10
XML Schemas in Z39.50

• Dublin Core XML format
• http//www.nlc-bnc.ca/bath/bp-app-d.htm
• http//www.openarchives.org/OAI/dc.xsd
• ExplainLite XML DTD
• http//www.one-2.org/technical/ONE-ICONE-DTD-0001.
  dtd
• Holdings XML Schema
• http//www.portia.dk/zholdings/Holdings6a/Holdings
  Schema6a_xsd/HoldingsSchema6a.htm
• ES Task Package XML format

11
Dublin Core (Bath Profile)

• ltrecord-listgt
• ltdc-recordgt
• ltcreatorgtsome authorlt/creatorgt
• ltcreatorgtsome authorlt/creatorgt
• lttitlegtsome titlelt/titlegt
• lt/dc-recordgt
• ltdc-recordgt
• .....
• lt/dc-recordgt
• lt/record-listgt

12
ExplainLite (VisualCat)
13
Holdings XML (danZIG)

• lt?xml version"1.0" encoding"UTF-8" ?gt
• lt!-- ZIG XML Holdings B-2/A danZIG example   --gt
• lt!-- Produced by Poul Henrik Jorgensen 2001-05-21
    --gt
• ltholdingsStructure xmlnsxsi"http//www.w3.org/20
  00/10/XMLSchema-instance" xsinoNamespaceSchemaLoc
  ation"http//www.portia.dk/zholdings/Holdings6a/H
  oldingsSchema6a.xsd"gt
• ltbibItemInfo-1 targetItemId-3"001 field in
  DanBib" /gt
• lt!-- holdingsStatement repeated for each
  location   --gt
• ltholdingsStatement-4 unionCatShelfMark-9"Local
  Shelf Mark" holdingsNotes-25"Holdings of
  serials"gt
• ltholdingsSiteLocation-6 targetLocationId-26"Ide
  ntificator in local system" institutionOrSiteId-27
  "Library Number" networkAddress-33"Z39.50URL"
  siteNotes-34"Availability" /gt
• ltunionCatLendingInfo-19 servicePolicy-109"1
  eller 2 cf. danZIG note" /gt
• lt/holdingsStatement-4gt
• lt/holdingsStructuregt

14
ILL transactions in XML

• ICCU/SBN system offers XML Item-Order request
  messages (APDU) via E-mail
• ONE-2 Profile of all ILL messages in XML
• http//www.portia.dk/pubs/ill/schema/illv2/illv2.h
  tm
• New danZIG Profile using XML for Z39.50/ILL
  Profile 1

15
Circulation Interchange Protocol

• NISO Circulation Interchange Protocol
• http//www.niso.org/commitat.html
• NCIP Data specified by XML DTD/Schema
• http//www.portia.dk/pubs/NCIP/NCIP_v0_1a.xsd
• Adapted to SOAP/WSDL
• http//www.portia.dk/pubs/NCIP/PortTypes.wsdl

16
ZML Objectives

• Initiative by Library of Congress and others
• Leverage investments in existing Z39.50 Services
  and specifications
• Simplify Z39.50 implementation
• Facilitate interoperability with other relevant
  standards
• Foster migration of Z39.50 functionality to
  mainstream IT technologies

17
ZML Z39.50 over SOAP

• Protocol elements encoded as XML Structures
• Relevant Z39.50 Services mapped to SOAP
  Request/Response functions over HTTP
• Search/Present and other services simplified
• Existing Web-to-Z gateways may be enhanced with
  SOAP-to-Z gateways
• Draft specifications to be presented at ZIG in
  October 2001 at British Library in York

18
Semantic Web and RDF

• RDF is part of W3C Semantic Web Activity
• http//www.w3.org/2001/sw/Activity
• Defines relationships and attributes of
  electronic resources
• Can represent any metadata schema, e.g. Dublin
  Core or IFLA FRBR metadata
• RDF is expressed by directed graphs or XML
• RDF is used to represent Authority Data and other
  metadata

19
FRBR RDF graph (VisualCat)
20
Summary

• XML offers many inherent advantages as data
  format
• XML standards are already implemented in relation
  to MARC, Z39.50, ILL and NCIP
• Next generation of Z39.50 (i.e. ZML) will most
  likely be based on XML standards
• Digital Libraries may be the killer application
  for RDF