Module Road Map
Assignment Road Map
Notice we have linked the conduit directly to the presentation
layer. This is normally a bad idea!
Introduction to XML
 How do we make all of these diverse technologies work
 Extensible Mark-up Language (XML)
 Origins in SGML (Standard Generalised Mark-up
 Late 1980 early 90s Tim Berners-Lee working in
Switzerland devised the first specification for HTML
based on SGML
Simple HTML Document
 Tags mark-up the content…
 Rendered as…
Problems with HTML
 The tags were defined as part of the language
 Different browsers added new features to the language
in order to compete
 Browser wars
The Marquee Tag
World Wide Web Consortium
 Devise standards and software related to the World
Wide Web
 Greater standardisation was applied to HTML leading
to XML
Applying Standards
 XML HTML, XHTML, Strict, Transitional
 We must be good boys and girls
 Apple, Opera and Mozilla devised an extension to
HTML called Web Forms 2.0
 HTML 5
Two Faces of the Web
 HTML 5 – Human Being
 XML – Systems
 E.g. Netflix - Facebook
 A meta-language - data about data
 May be used to define other mark-up languages
 XML may be used in many other non web related
contexts (Office Documents)
 Allows us to split data from presentation
Media Centre Master
 Tool to manage films saved as DivX files
 Creation of scan folders
 Communicates with the Internet Movie Database
 Web service
 Web page versus web document
Viewed in Windows Media Centre
Viewed at IMDB
Tags in XML
 XML doesn’t define a large range of tags
 If we want to create a new tag in XML we don’t need to
wait for a new version of the language
 XML allows us define our own mark-up languages
 XHTML (eXtensible HyperText Markup Language)
 Document Type Definition contains a set of rules that
define what are allowable tags in an XHTML file
The XML Declaration
 The top line of the file reads as follows...
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
 XML Version (1.0 or 1.1 – only interested in 1.0)
 Encoding – utf-8
 Everything we see on a computer is internally
represented as binary data
ASCII (American Standard Code for UNICODE
Information Interchange)
Uppercase A
Uppercase B
Uppercase C
Uppercase D
Uppercase E
Uppercase F
Uppercase A
Uppercase B
Uppercase C
Uppercase D
Uppercase E
Uppercase F
 How do we translate the following? - 46, 41, 44, 45
The Root Element
 A tag that encloses all of the data in the file and must
not be empty
 XML file for 28 Days Later has a root element of
 <LocalTitle>28 Days Later</LocalTitle>
 Opening tag
 Closing tag
 Data
28 Days Later
Attributes and Values
 Added to elements to include additional data
 (Modified structure to illustrate attributes and values)
Five Rules of XML
 1. Tag names are case sensitive
 This is ok...
<LocalTitle>28 Days Later</LocalTitle>
 This is not...
<LocalTitle>28 Days Later</Localtitle>
 These are two different tags
<localtitle>28 Days Later</localtitle>
<LocalTitle>28 Days Later</LocalTitle>
Five Rules of XML
 2. Every opening tag must have a closing tag
 This is good...
<LocalTitle>28 Days Later</LocalTitle>
 This is bad...
<LocalTitle>28 Days Later
Five Rules of XML
 3. A nested tag pair cannot overlap another tag
<Name>Alex Palmer</Name>
<Name>Alex Palmer</Name>
Five Rules of XML
 4. Attribute values must appear within quotes
 Good...
<FilmDetail Title="28 Days Later" IMDBrating="7.6" ProductionYear="2002">
 Bad...
<FilmDetail Title=28 Days Later IMDBrating=7.6 ProductionYear=2002>
Five Rules of XML
 5. Every document must have a root element

Slide 1