1. WHAT THE HELL IS XML?

2. What the Hell is XML? What the hell is XML?  Markup Language  Derived from SGML (Standardized General Markup Language)  Describes the CONTENT (stylesheet has to be applied to format content)  Structured documents, can be used like a database that you can send to your clients/suppliers  They can then use the data in any XML-supporting database/app

3. What the Hell is XML? Like HTML?  Both based on SGML  Both use tags  In both, tags enclose content.. ..content..  In both, tags have attributes.. 

4. What the Hell is XML? Like HTML?  XML MUST have closing tags  This is a paragraph  This is invalid in XML  MUST have quotation marks around attributes  No quotes  CaSE senSiTivE!  This will not close  XML has a strict syntax  Documents must be well-formed!  XML documents must start with an xml tag.. 

5. What the Hell is XML? Object Modelling   Irfan  770-980-0099   Michelle  678-357-3661   In a database, Apogee would be the database name, Employee would be the Table, Name and Phone would be columns  In object models, Employee would be the object, Name and Phone would be Properties

6. What the Hell is XML? Attributes   Irfan  678-981-0193  770-980-0099   Joel  678-357-3661   Debate over when to use attributes and when to use elements  MS XML tends to use attributes by default (faster to process?)  Standard XML used elements more

7. What the Hell is XML? XML – The Rules  Document Type Definitions (DTDs)  Give the rules for validating documents  A bit like a database schema/object model  Describes the rules of the structure Relationships between elements (e.g. one to many) Which elements contain which other elements In Backus Naur Form (BNF) – obscure?  XML Schemas  For a similar purpose to DTDs  Are taking over from DTDs  Are expressed in XML …

8. What the Hell is XML? XML – The Rules  Referencing a DTD  http://www.w3.org/TR/REC-html/strict.dtd  The above is the strict DTD for DHTML (HTML 4)

9. What the Hell is XML? XML Editors  Schema Editors  Some allow you to turn a DTD into a schema  XML Spy  Turbo XML  Schema Verifiers  Only check the doc is well formed  Expat http://www.jclark.com/xml/expat.html  Schema Validator  World Wide Web Consortium http://www.w3.org/2000/09/webdata/xsv  XML Parser  Xerces Java  http://xml.apache.org/xerces-j/ http://xml.apache.org/xerces-j/