Case Study - The Ridge Tool Co.   Table of contents   Indexes   Overview of XSL
 

Overview of the XML Family of Standards

Goulde, Michael
Patricia Seybold Group
 		Michael  Goulde
Sr. Consultant, V.P.,  Patricia Seybold Group 
 

XML Is a Metalanguage

  Used to define domain vocabularies. Some vocabularies relate to horizontal domains. Others are vertical domains Can be used for private vocabularies as well.
 

Where XML Is Being Implemented

 XML is being used within Web applications, Distributed computing environments, and for Web Document Publishing.
 

W3C Recommendations & Working Groups

 There are several W3C Recommendations. These include:
 
  • XML 1.0
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  • Document Object Model (DOM)
    •  Many of the newest XML-based Web standards are still in working groups. Working Groups include:
     
  • Extensible Style Sheets (XSL)
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  • XML Linking Language (XLink)
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  • XML Pointers (XPointer)
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  • XML Namespaces
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  • Resource Description Framework (RDF)
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  • XML schemas
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    XML 1.0 Recommendations

     The XML Recommendation is designed to make SGML usable on the Web. It can be characterized as:
     
  • Metalanguage for defining markup languages
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  • Subset of SGML HTML is a single application of SGML
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  • Minor differences between XML and SGML
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  • Separate content from presentation
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  • Provide structure to content
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  • Public specification
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  • All XML Documents Are Well Formed
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    Document Object Model (DOM) Recommendation

     DOM is desigined to make:
     
  • HTML and XML documents dynamic
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  • Accessible to internal scripts and external programs
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  • Standard way of doing DHTML
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  • Provides programmatic interfaces into document components
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  • Platform and language independent
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    Extensible Style Language (XSL)

     XSL is a subset of Document Style Semantics and Specification Language (DSSS). It is designed to provide:
     
  • Reusable formatting
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  • Presentation and transformation
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  • More powerful formatting
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  • Writing direction independence
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  • Associate behavior with elements through scripts
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    Extensible Linking Language: XLink

      XLink provides a way to externalize links Provides one-to-many, many-to-one, and many-to-many linking mechanism. XLink:
     
  • Allows user-defined links
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  • Richer, easier to maintain links
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  • XPointer: addresses into the structure of document (link to third chapter)
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    Resource Description Framework (RDF)

     RDF provides a foundation for processing metadata. RDF includes:
     
  • Resources, content descriptions and content relationships, describe collections, describe rights and privileges, more
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  • RDF addresses need to make schema machine readable
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  • XML syntax is only one possible syntax for RDF
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    XML Data Schema Proposals

      DTDs lack several critical characteristics. DTDs are not specified in XML syntax. No data typing or way to describe relationships. Many proposals for XML data schema vocabularlies. XML Schema, XML Data, Document Content Descriptor (DCD. It is likely one specification will emerge when the standards process is complete.
     

    XML Vocabulary Domains

     XML Vocabularies, or tag sets can have either a horizontal, or cross industry domain, or a vertical or industry specific domain.
     

    Horizontal Domains

     Horizontal Domains are W3C specifications that use the XML syntax and apply to a particular domain. Examples of horizontal domains include:
     
  • Mathematical Markup Language (MathML)
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  • Synchronized Multimedia Integration Language (SMIL)
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  • Platform for Privacy Preferences Project (P3P)
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  • Resource Description Framework (RDF)
    •  Some of the new horizontal domain definitions are outside the W3C standards process. These include:
     
  • Channel Definition Format (CDF)
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  • Open Software Description (OSD)
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  • Dozens of others
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    Vertical Domains

     Generally vertical domains are developed by groups of companies in an industry. These are vertical industry specific. Examples include:
     
  • XML/EDI SIG
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  • CommerceNet
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    Industry Vocabularies

     
  • Open Buying on the Internet (OBI)
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  • Outgrowth of the Internet Purchasing Roundtable
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  • Procurement of hi vol./low value goods and services
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  • Open Trading Protocol (OTP)
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  • Offer/invoice/payment and delivery receipt
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  • Key elements of electronic purchases
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  • Open Financial Exchange (OFE)
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  • Internet Content & Exchange (ICE)
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  • Commercial transactions
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  • HL7 V3 - Standards for Healthcare Data Interchange
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    Summary

     XML specifications inherit legitimacy and platform independence from SGML, the ISO standard from which XML was derived. Today Industry groups are using XML as standard meta language. Some XML application standards are governed by the W3C. Others are proprietary specifications. It is always important to be clear which are formal specification efforts, proposals, and which are proprietary specifications.
    Case Study - The Ridge Tool Co.   Table of contents   Indexes   Overview of XSL