XML at Work

1
XML at Work

• John Arnett, MSc
• Standards Modeller
• Information and Statistics Division
• NHSScotland
• Tel [phone] (x2073)
• mailtoJohn.Arnett_at_isd.csa.scot.nhs.uk
• http//isdscotland.org/xml

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Contents

• XML Usage
• Enabling Technologies
• XML Applications
• XML Messaging and Web Services
• XML in Presentation
• XML in Application Logic
• XML Data Storage and Content Management

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XML Usage

• Key features

• Human readable
• Structured and searchable
• Separates data from presentation
• Self-describing
• Extensible any number of tags allowed
• Meta-markup language

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XML Usage

• Open standard, promoted by many vendor-neutral
  organisations, incl.
• W3C
• OASIS (Organization for Structured Information
  Standards)
• HL7 (Health Level 7)
• OMG (Object Management Group)
• UK Government

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XML Usage

• Widely supported by software vendors and open
  source groups, incl.

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Enabling Technologies

• XPath (XML Path Language)

• Language for locating parts of a document
• Provides a syntax for navigating XML document
  trees
• Designed for use by XSLT and XPointer

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Enabling Technologies

• XLink (XML Linking Language)

• Language for linking resources

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Enabling Technologies

• XPointer (XML Pointer Language)

• Language for referencing specific points in a
  document
• Uses XPath
• May be used with XLink to reference specific
  points in linked documents

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XML Applications
Data Storage Content Management
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XML Messaging

• XML Messages

• Ideal for data interchange
• Text based
• Open
• Self describing
• Extensible
• Exchanged between applications on the same
  network or over the Internet/Extranet

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XML Messaging

• XML Business Vocabularies, e.g.

• Health Care
• Health Level 7, v3
• Government
• UK GovTalkTM schemas
• B2B transactions
• ebXML
• Financial Services reporting
• XBRL

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Web Services

• Set of emerging standards, incl. SOAP, WSDL and
  UDDI

• Allow systems to communicate over the internet
  using XML messages
• Used for
• remote lookups and service calls
• enterprise application integration
• electronic B2B exchange

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Web Services

• SOAP (Simple Object Access Protocol)

• Lightweight, XMLbased protocol for exchanging
  information over the internet
• Language, platform and transport independent
• v1.2 W3C Recommendation

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Web Services

• WSDL (Web Services Definition Language)

• XML-based language for describing services
  available on the internet

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Web Services

• UDDI (Universal Description, Discovery and
  Integration) directory services

• Information Services
• business details (white pages)
• business categories (yellow pages)
• available services (green pages)
• Operations
• service registration
• finding and using services

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XML for Presentation

• XHTML (Extensible HTML)

• Developed by WC3 as XML-based successor to HTML
• Written using well-formed XML
• Backwards compatible
• Current version (1.1) designed to be extended
  using modules

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XML for Presentation

• XSL (Extensible Stylesheet Language)

• Enables XML to be presented in other XML or
  non-XML formats esp. as HTML
• v1.0 W3C Recommendation
• Can be used to create dynamic web-forms, e.g.
  WSDL to HTML

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XML for Presentation

• Other XML presentation technologies

• WML (Wireless Markup Language) for mobile devices
• SVG (Scaleable Vector Graphics)
• Scientific vocabularies
• CML (Chemical Markup Language)
• MathML (Mathematical Markup Language)

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XML in Application Logic

• DOM (Document Object Model)
• API for in-memory document manipulation using a
  node-based tree structure

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XML in Application Logic

• SAX (Simple API for XML)
• Alternative, event-driven API, used for parsing
  large documents

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XML Data Storage

• Document storage solutions incl.

• Web and file servers
• XML enabled databases
• Native XML repositories/databases

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XML Data Storage

• XQuery

• Enables SQL-like querying of XML documents using
  XPath
• W3C Working draft

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XML Content Management

• RDF (Resource Description Framework)

• W3C recommendation for describing information
  contained in web resources
• i.e. anything that can be addressed with a URL
• Dublin Core is an RDF vocabulary for describing
  web pages

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XML Content Management

• Microsoft CDF (Channel Definition Format)

• Used to automatically send (or push) web content
  to subscribers
• e.g. subscibers can obtain regular news updates
  from a news website
• RSS (Rich Site Summary) is a smilar application
  developed by Netscape

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XML Content Management

• Topic Maps

• Framework for indexing data and document
  resources using URIs
• Consist of
• topics
• associations
• occurences
• XML Topic Maps (XTM) 1.0 Specification ISO
  Standard 13250

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The XML Standards Family
XHTML
HTML
SGML
Adapted from http//www.idealliance.org/XMLRoadmap
/WEB/xmlstdill.htm
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In Summary

• Open standard, widely supported by many
  organisations
• Applications include
• Messaging and web services
• Presentation and application logic
• Data storage and content management

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Find Out More

• World Wide Web Consortium
• www.w3.org

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Messaging and Web Sevices

• W3C Web Services Activity
• www.w3.org/2002/ws/
• Web Services Interoperability
• www.ws-i.org
• XMethods
• www.xmethods.org/
• Enterprise Integration Patterns
• www.enterpriseintegrationpatterns.com

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XML Vocabularies

• Scottish Health and Community Care XML Steering
  Group
• www.isdscotland.org/xml
• GovTalk Schemas and Standards
• www.govtalk.gov.uk/schemasstandards/schemasstandar
  ds.asp
• Health Level 7
• www.hl7.org

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XHTML and XSL

• W3C HyperText Markup Language (HTML) Home Page
• www.w3.org/MarkUp/
• The Extensible Stylesheet Language Family (XSL)
• www.w3.org/Style/XSL/