Friday, November 7, 2014

Week 10: XML

1. Martin Bryan.  Introducing the Extensible Markup Language (XML): http://www.is-thought.co.uk/xmlintro.htm   
2. Extending you Markup: a XML tutorial by Andre Bergholz : http://xml.coverpages.org/BergholzTutorial.pdf 

3. XML Schema Tutorial http://www.w3schools.com/Schema/default.asp   


XML: subset of SGML (Standard Gen. Markup Lang.)
  • clearly mark boundaries of elements in DTD (Doc Type Def)
    • dec: <!DOCTYPE>
    • con: namespaces + DTD don't work well together
  • this delineation enforces strict implementation
    • ex. 1st-level heading implemented before 2nd-level, etc. 
  • extends link capabilities w/ 3 supp. lang
    • Xlink: 2 docs
    • XPointer: individual parts of XML doc
    • XPath: used by previous to describe loc paths
      • loc path: axis, node test, predicate
  • XML not designed to be standardized
    • multiple files for compound docs

XML docs: formal syntax for series of entities
  • ea. entity can contain 1+ elements
  • ea. element can contain 1+ attributes (process)
  • 3 types of markup
    • document instance (what kind)
    • optional: processing instruction (how to read)
    • optional: doc type declaration (formal markup declarations)

Use
  • markup tags (defined by trade org or other body)
    •  e.g. <to> content </to>
  • possible to define own sets
    • create DTD w/ formal id of relationships b/w elements
    • and also define attributes

Standard and non-standard text elements (??)
  • commonly used text: text entity
  • non-standard: system-dependent entities can be declared

Illustrations and other special elements
  • special notation either as entity or attribute
  • notation declaration
    • to designate action for unparsed data in ref file

 

XML schema
  • allows user to define data types
  • goal: to replace DTDs
  • 4 schema
    • DDML: doc def markup lang
    • DCD: doc content desc
    • SOX: schema for object-oriented XML
    • XML-Data (replaced by DCD)

Example

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.mypage.com/">

<xs:element name="content">
</xs:element>
</xs:schema>

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