An Introduction to XML

Reference: Lars Maris Garshol And Other Introductory Concepts Markup Language

 Codes/Tags are used for structuring a document  Special software is required to process the language  Convenience for managing and processing the documents  Special or Generalized markup language (as TEX/HTML versus SGML) Example of an HTML Document

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…… What’s wrong with HTML?

 Presentation according to user’s environment is difficult  Processing the information automatically is not easy  Lots of elements should be maintained  Little internal structure  Other than HTML, SGML doesn’t define the data format for display XML is Coming Up (1/2)

A simplified version of SGML A document is more precisely encoded by defining your own markup language Programs can understand and process the document much better Develop a common standard for linking to support linking between more than one resources and can be outside the document XML is Coming Up (2/2)

Transformation using XSL, which is a simplified version of DSSSL Versatile ways of displaying documents Better ways for searching and agents Enable information exchange between different systems The Ingredients of an XML Document

A processing instruction containing an XML declaration Document type declaration and a root element Other elements Attributes and comments An XML Document (1/2) Steve Hoenisch [email protected]

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An XML Document (2/2)

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… Well-formed XML Documents  Declaration, such as  Root element  (symmetric type) and  (asymmetric type)  Tags can be nested but not intermixed  Case sensitive  “attribute”  Uniqueness within an element (sub-elements or attributes)  Special characters (using entity reference) &,>,”  for comments Family of XML Technologies (1/2)

XSL DTD and XML Schema XLink, XPath, XPointer Namespace DOM and SAX Further evolving standards: XQuery, XML Base, XML Signature, MathML, SMIL, SVG, VoiceXML, … Family of XML Technologies (2/2)

Display – XHTML, CSS, XSL-FO Transformation & Query – XSLT, XPATH, XQUERY Parsing – SAX, DOM, sTAX Security – XML Encryption, SAML, XACML Semantic Web – RDF, OWL Web Services – SOAP, WSDL, UDDI, REST Web View – MXML, XAXML XML for Configuration Data

XML as a data format to store configuration data Extra characters for the convenience of XML XML processing API is required The cost of flexibility XML for Transferring Data

Intra-application data transfer

Inter-application data transfer

Used for Web Services XML for Applications

One simple information model rather than multiple data models accommodating each application function. Change the behavior and functionality of application programs by changing the underlying XML rather than changing code Optimize performance by changing the way information is expressed Ten Predictions for XML (by Elliotte Rusty Harold in 2007 ) 1. XQuey is becoming mature 2. Atom Publishing Protocol (APP) is ready to publish contents that all servers can implement 3. XFORMS is coming up (such as SVG + XFORMS for logos) 4. XProc specifies what to do an XML document in which order 5. Semantic Web is taking off Ten Predictions for XML (in 2007)

6. OpenDocument (against office open XML) 7. XML in the client (XSLT is fully supported) 8. WS-* has peaked 9. The Browser wars continue 10. XML backlash and the counterrevolution (why not XML?) Watch out “Deep Web” technology, such as cloud computing, data mining, recommend systems, information retrieval, clustering, classification, feature extraction, and so on.