XML for Dummies (and managers)

1. XML for Dummies (and managers) • Mark Pascall • Technical Architect

2. Overview • What is XML? • Extensible Markup Language • Many pieces in the XML puzzle • Very fast moving • First – back to basics…. XPointer Xlink HTML XML XML Schema XSLT Namespace XQuery SOAP

3. How the Internet works…. Get me that text file OK here it is Web Clients (Browser) Web Server

4. Hypertext Mark-up Language <h1>Here is the title</h1> <p>This is a piece of <b>Text</b> </p> • A formatting language • Browser knows how to interpret the tags.

5. What is Extensible Markup Language? • NOT a markup language • Meta-markup Language • Set of very simple rules • XML provides a uniform method for describing and exchanging structured data • Describes structure and semantics, not formatting

6. Meta Language • Use letters of alphabet. • Spaces between words. • Read from left to write. • ….. French English German …..

7. XML Specification • Tags must not overlap • Tags case-sensitive • Must have root tag • …… SVG WML MathML …..

8. The XML Rules…. • Single, unique root element • Matching open/close tags • Consistent capitalisation • Correctly nested elements (no overlapping elements) • Attribute values enclosed in quotes • No repeating attributes in an element <?xml version=“1.0”?> <company id=“4859”> • <name>3Months.com</name> • <type>Web Development</type> • <address> <street>Wakefield st</street> <city>Wellington</city> <country>New Zealand</country> • </address> </company> Well Formed

9. History of XML • Standard Generalised Markup Language • Been around since early 90’s • XML is a sub-set of SGML (SGML-lite) • XML has smaller and simpler syntax • SGML’s development provides the foundation for XML • XML is therefore not “bleeding edge”

10. Why XML is so powerful • Provides international, vendor independent standard for describing information • Any information – structured or unstructured XML HTTP TCP/IP

11. XML Markup languages/vocabularies • Remember XML is a meta-language • Anybody can create their own language • Why would you want to? • Each language designed for a specific purpose….

12. Mathematical Markup Language (MathML) x2 + 4x + 4 =0 <apply><plus/> <apply><power/> <ci>x</ci> <cn>2</cn> </apply> <apply> <times/> <cn>4</cn> <ci>x</ci> </apply> <cn>4</cn> </apply>

13. Synchronized Multimedia Integration Language (SMIL) <DIV CLASS=“time” t:timeline=“seq”> <P class=“time” t:dur=“1”> This appears for one second and goes away </P> <P class=“time” t:dur=“1”> This appears after one second, remains visible for one second and goes away </P> <P class=“time” t:dur=“1”> This appears after two seconds, remains visible for one second and goes away </P> </DIV>

14. Vector Markup Language <v:shape style=‘top: 0; left: 0; width: 250; height: 250’ stroke=“true” strokecolor=“red” strokeweight=“2” fill=“true” fillcolor=“green” coordorigin=“0 0” coordsize=“175 175”> <v:path v=“m 8,65 l 72,65,92,11,112,65,174,65,122,100,142,155,92,121,42,155,60,100 x e”/> </v:shape>

15. Wireless Markup Language <wml> <!-- root element --> <card id="card1" title="Example 1"> <p> <!-- a card can only contain P blocks or DO blocks --> <do type="accept" label="go to card 2"> <go href="#card2"/></do> This is the first card. </p> </card> <card id="card2" title="Example 1"> <p> This is the second card. </p> </card> </wml>

16. Hypertext Markup Language (HTML) <h1>The Title</h1> <p>This is a piece of <b>HTML </b> </p> • Or is it?? • Next version of HTML = XHTML

17. XML Schemas and DTDs • XML is about communication • Need to speak the same language • Schemas/DTDs describe the vocabulary of the language • i.e. what tags are used and how they can be organised • Schemas will replace DTDs

18. An Example Schema <?xml version="1.0" encoding="UTF-8"?> <PressRelease> <Title>Studend Loan Problems</Title> <Date>20/7/01</Date> <Content>Bla Bla Bla</Content> </PressRelease> <?xml version="1.0" encoding="UTF-8"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> <xsd:element name="PressRelease"> <xsd:complexType> <xsd:sequence> <xsd:element name="Title" type="xsd:string"/> <xsd:element name="Date" type="xsd:date"/> <xsd:element name="Content" type="xsd:string"/> <xsd:element name="Author" type="xsd:string" minOccurs="0"/> </xsd:sequence> </xsd:complexType> </xsd:element> </xsd:schema>

19. Introducing XSL-T • Extensible Stylesheet Language • Standard ratified this year by W3C • Way of transforming an XML document into another document

20. Transformation XSLT document Text XML document HTML XSLT Processor XML

21. Summary • The XML Specification = Meta-language for describing XML Mark-up languages • XML Schemas (and DTD’s) describe the structure of a particular XML Mark-up language • XSL-T documents transform XML document into another format (HTML, XML etc)

22. XML in Action – a case study

23. Agenda • Case study background • Choosing a DTD/Schema • Creating XML – the options • Storing XML – the options • Presenting XML – the options • Solution Benefits • Demo

24. Case study background • October 2001 – won contract to redevelop E-government website (www.e-government.govt.nz) • Business requirements • Usual stuff (accessible, usable etc) • Guidelines compliant (squeaky clean) • “Content must be made available in a standard HTML format. Where information is provided in a proprietary format an alternative HTML version must also be made available.” • Can’t just put it up as a PDF anymore • Simple publishing process • Future-proofed • Constraints • Limited budget • Tight timeframe

25. Traditional options • Static site • Did not give simple publishing process for “unskilled” people • Content Management System • Store information in RDBMS • Not good for “document centric” applications • Cost, timeframe, simple workflow requirements

26. The challenge • To create a system that allows non-technical authors to publish to guidelines compliant HTML (and eventually other formats) • The solution • XML

27. Choosing a DTD/Schema • Make up your own • Don’t reinvent the wheel! • Xml.org • We selected a subset of DocBook • Could handle all the information we needed to store • Supported by a growing number of products • NZETC uses TEI

28. Creating XML – the Options • Use an XML editor • E.g. XML Spy, Xmetal, Framemaker etc • Allow you to create a document that conforms to a specified DTD/Schema • Problem: everybody potentially an author • Convert Word documents to XML • Styles

29. HTML (Internet) XSL-T for convertion Word (using Styles) DocBook XML eBook Anything you want!! Word is authoritative source

30. Xcon Demo

31. Storing XML – the Options • Relational database • Native XML Repository • E.g. Excelon, Tamino, Ipedo, Xindice • First generation products • At the time too immature/expensive • On the file system

32. Presenting XML – the Options • Publishing to humans • Need to “transform” XML to a format appropriate for humans • Physical print – out of scope • HTML obvious choice • XSL-T to transform XML to HTML • Not the only way to present to humans • SMIL, SVG, MathML etc • Audience must have software • What about publishing “Raw” XML?

33. Organisation B Website Organisation C Website Organisation A Website XML document XML document HTML document HTML document

34. Demo