1. XML A brief introduction ---by Yongzhu Li

2. XML --- a brief introduction 2 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XML eXtensible Markup Language designed to describe data. a family of technologies platform-independent free and extensible

3. XML --- a brief introduction 3 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Basic Concept a markup language is a mechanism to identify structures in a document. the XML specification defines a standard way to add markup to documents. a meta-language for describing markup languages provides a facility to define tags and the structural relationships between them

4. XML --- a brief introduction 4 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Background SGML Standard Generalized Markup Language (ISO 8879) provides arbitrary structure, but too difficult to implement just for a web browser. HTML A subset of SGML with a fixed tag semantics and set, lack of flexibility and extensibility Lack of extensibility

5. XML --- a brief introduction 5 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Background II XML simplified SGML, extensible looks like HTML but isn't HTML any fully conformant SGML system will be able to process XML documents but, XML documents does not require a system that is capable of the full conformance of SGML

6. XML --- a brief introduction 6 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Evolving History W3 Consortium began work in Aug. 1996 XML 1.0 Released by W3C on Jan. 10, 1998 XML 2.0 Introduced on Oct. 6, 2000 XML 3.0 Under drafting and evaluating

7. XML --- a brief introduction 7 CSI668 Topics in System Architecture SUNY Albany Computer Science Department What XML looks like prolog --- XML file declaration comment processing instruction, PI element and its attribute 15.50

8. XML --- a brief introduction 8 CSI668 Topics in System Architecture SUNY Albany Computer Science Department First Sample single XML file only provide structured data No formatting information browser don’t know how to display a single XML document

9. XML --- a brief introduction 9 CSI668 Topics in System Architecture SUNY Albany Computer Science Department CSS Cascading Style Sheets also work well with HTML delaring CSS within XML file separate data content with its form only provide formatting information, lack of manipulation on data

10. XML --- a brief introduction 10 CSI668 Topics in System Architecture SUNY Albany Computer Science Department First Sample II FormatedFormated Source CSS fileSourceCSS file

11. XML --- a brief introduction 11 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Interesting CSS Cascading layers z-index position sample XML CSS

12. XML --- a brief introduction 12 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Interesting CSS II Filter filter:glow(color=blue, Strength=5); sample XML CSS

13. XML --- a brief introduction 13 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XSL eXtensible Stylesheet Language declaring XSL within XML transform XML to HTML file defining and formating XML parts and patterns far more sophisticated but powerful than CSS

14. XML --- a brief introduction 14 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XSL by Sample Data SortingData Sorting XSL SourceXSL Source Data FilterData Filter XSL SourceXSL Source

15. XML --- a brief introduction 15 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Namespace a collection of element type and attribute names distinguish between duplicate element type and attribute names

16. XML --- a brief introduction 16 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Namespace Samples ….. …..

17. XML --- a brief introduction 17 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Name Space Sample II some message email me

18. XML --- a brief introduction 18 CSI668 Topics in System Architecture SUNY Albany Computer Science Department DTD Documents Type Definition a model for describing the structure of information. Well formed XML and Valid XML A valid XML must follow a specific DTD

19. XML --- a brief introduction 19 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Why DTD Independent organizations use a common DTD for interchanging data. applications use DTD to verify the data received from the outside world is valid.

20. XML --- a brief introduction 20 CSI668 Topics in System Architecture SUNY Albany Computer Science Department DTD II Declaring DTD within XML Element Declaration within DTD Attribute Declaration Eric: Parsable Character Data Eric: Parsable Character Data

21. XML --- a brief introduction 21 CSI668 Topics in System Architecture SUNY Albany Computer Science Department DTD Weakness written in a different (non-XML) syntax. don’t support namespace only offer extremely limited data types. have a complex and fragile extension mechanism

22. XML --- a brief introduction 22 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Schema replacement of DTDs for XML more primitive data types namespace support. itself is a well formed XML and validated by Schema DTDs

23. XML --- a brief introduction 23 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XML Application Domain Electronic Data Interchange search engine web application distributed documentation and computing

24. XML --- a brief introduction 24 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Some other XML applications WMLWML, Wireless Markup Language CML, Chemistry Markup Language and MathML OSD, Open Software Description OFX, Open Financial Exchange

25. XML --- a brief introduction 25 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XML Application Structure Viewer #1 e.g. Retail Agent Viewer #2 e.g. Customer XML Processor Application Server DB 1 DB 2 DB.. DB n May be heterogeneous DBs Other process CSS/ XSL translation

26. XML --- a brief introduction 26 CSI668 Topics in System Architecture SUNY Albany Computer Science Department DOM Document Object Model program interface for XML represents a tree view of the XML documentElement as a root childNode for other branch each node is an object Node Interface Model

27. XML --- a brief introduction 27 CSI668 Topics in System Architecture SUNY Albany Computer Science Department SAX the Simple API for XML another programming interface for XML event-based API use call-back functions to handle parsing event SAX and DOM are two major APIs for XML application development.

28. XML --- a brief introduction 28 CSI668 Topics in System Architecture SUNY Albany Computer Science Department SVG Scalable Vector Graphic XML application describe two-dimensional vector graphic shapes, images and text reduced the network traffic reduced server overload VML by Microsoft and PGML by Adobe

29. XML --- a brief introduction 29 CSI668 Topics in System Architecture SUNY Albany Computer Science Department XHTML eXtensible HTML HTML defined by XML well-formed HTML tag names must be in lowercase

30. XML --- a brief introduction 30 CSI668 Topics in System Architecture SUNY Albany Computer Science Department Things under going… Xlink and Xpointer allows elements to be inserted into XML in order to create and describe links between resources provide multi-directional hypertext and hypermedia support proposal recommendation on Dec. 20, 2000 XML Protocol to develop technologies which allow two or more peers to communicate in a distributed environment, using XML as its encapsulation language. requirement draft on Dec. 19, 2000

31. Thank You 谢谢