Beyond HTML: Extensible Markup Language (XML) http://dli.grainger.uiuc.edu/Publications/XMLTutorial

1
Beyond HTML Extensible Markup Language
(XML)http//dli.grainger.uiuc.edu/Publications/X
MLTutorial

• Tim Cole
• Tom Habing
• Grainger Engineering Library Information Center
• University of Illinois at UC
• t-cole3_at_uiuc.edu
• 2 June 2000

2
Text as Ordered Hierarchy of Content Objects

• E.g. A book contains chapters, which contain
  paragraphs, which contain sentences, ...
• This model (DOM) underlies SGML, HTML, XML
• Content Objects can be Presentational (e.g., as
  in HTML) or Descriptive (e.g., as in SGML, XML)
• Allowed Object Names can be Finite (as in HTML)
  or Extensible (as in SGML, XML)
• Thus SGML XML are often described as meta
  markup languages

3
ML Basics - Markup Content

• Markup (Tags) ltauthorgtlt/authorgt ltempty_tag /gt
• Content ltauthorgtJ. L. Penalt/authorgt ltauthorgtltfnam
  egtJ. L.lt/fnamegtltlnamegtPenalt/lnamegtlt/authorgt
• Attributes ltauthor sequencefirstgtJ. L.
  Penalt/authorgt
• Entities ltauthor ida1gtJ. L. Pe241alt/authorgt
  ltauthor ida1gtJ. L. Pentildealt/authorgt
• Others lt!--comments--gt lt?processing
  instructions?gt

4
Markup Language Differences

• XML Stricter Than HTML or SGML
• Must Close ALL Tags
• Attributes MUST BE Enclosed in Quotes
• All Mark-Up is CASE-SENSITIVE
• XML/SGML no fixed tags, no predefined style
• XML/SGML Are Extensible
• Fixed Elements (HTML) vs. Rules (XML, SGML)
• XML Tags Can Describe the Content
• XML Simpler Than SGML, Optimized for Web

5
Well-formed XML vs. Valid XML

• If a Document Follows the Syntactic Rules for
  XML, it is WELL-FORMED.
• Matching open and close tags
• No overlapping content objects (regions)
• Correct use of markup delimiters, entities, etc.
• Only Entities Allowed in Well-Formed are Unicode,
  gt lt quot and amp
• If it Also Adheres to the Content Models as
  Defined in a Document Type Definition, it is Also
  VALID.

6
Document Type Definition DTD

• Defines Allowable Content Models, Attributes,
  Entities for a Class of XML Documents.
• lt!ELEMENT book_collection (book) gt
• lt!ELEMENT book (isbn, author, title) gt
• lt!ATTLIST book id ID IMPLIED edition CDATA
  REQUIREDgt
• lt!ELEMENT isbn (PCDATA) gt
• lt!ENTITY ntilde ñ gt

7
First Demonstration

• Create a Simple, Well-Formed XML Document, using
  MS Notepad
• Book, Author, Title, ISBN, Link
• Open File in MS Internet Explorer
• Attach a CSS style sheet
• Re-Open in MS Internet Explorer

8
Typical XML File

• lt?xml version1.0 encodingutf-8 ?gt
• lt?xml-stylesheet href typetext/css ?gt
• lt!-- My First XML --gt
• lt!DOCTYPE root SYSTEM gt
• ltroot xmlnsdli gt
• document content ...
• lt/rootgt

9
Style Sheets CSS XSLT

• Cascading Style Sheets
• On-Screen Formatting Presentation
• Work with Both HTML XML
• Extensible Style Sheet Language Transformations
• Transforms Between XML DTDs or XML to HTML
• Allows Re-Ordering of Content, Selective Display
  of Content, Insertion of Generated Content
• Extensions Allow Dynamic Modification of Content
• Available as Application Programming Interface

10
XML Namespaces

• Allows Mixing of Multiple XML Schemas
• XML Documents that Also Contain Fragments of HTML
• Simultaneous Support of Multiple Metadata Schemas
  (e.g., Resource Description Framework, Dublin
  Core, UIUC DLI Metadata Schema)
• Rules for Namespaces Other Schema Extension
  Models Still Under Development

11
Advanced Demo

• Add Doctype Declaration (for Valid XML)
• Open DTD in XML Authority
• Open File in XML Notepad, XML Pro, XMetaL
• Attach an XSL Stylesheet
• Open in MS Internet Explorer
• Server Side Implementation of an XSL Stylesheet
• MS SQL Server 2000 -- Data to XML
• Script to load XML into database

12
Examples from DLI

• Full-text Article Examples
• A Large-Scale XML Testbed
• RDF / DC / IDLI Metadata
• Interoperability Using XML Namespaces
• Browsing the ASM Metals Handbook in XML
• Selective Display of Content Using XSLT
• ACES Agronomy Handbook in XML
• Dynamic Table of Contents Using XML DOM

13
Future Directions

• XML and Databases
• XHTML -- Next Generation HTML
• Schemas -- Next Generation DTDs
• Xlink/XPointer -- Advanced Linking
• Xforms -- Advanced HTML Forms
• MathML -- Mathematics markup
• SVG -- Scalable Vector Graphics markup

14
Tools for Authoring XML

• Notepad
• XML Notepad
• XML Pro
• XML Authority
• XMetaL
• ArborText