Module Road Map

Assignment Road Map

Notice we have linked the conduit directly to the presentation layer. This is normally a bad idea!

Credit CategoriesAssignment 2 –

1 2 3

Introduction to XMLHow do we make all of these diverse

technologies work together?Extensible Mark-up Language (XML)Origins in SGML (Standard Generalised

Mark-up Language)Late 1980 early 90s Tim Berners-Lee working

in Switzerland devised the first specification for HTML based on SGML

Simple HTML Document

Rendered as…

Tags mark-up the content…

Problems with HTMLThe tags were defined as part of the language

specification

Different browsers added new features to the language in order to compete

Browser wars

The Marquee Tag

World Wide Web Consortium (W3C)Devise standards and software related to the

World Wide Web

Greater standardisation was applied to HTML leading to XML

XMLA 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 MasterTool to manage films saved as DivX filesCreation of scan foldersCommunicates with the Internet Movie

Database

Web serviceWeb page versus web document

Viewed in Windows Media Centre

Viewed at IMDB

Tags in XMLXML doesn’t define a large range of tagsIf 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)

XHTML

Document Type Definition contains a set of rules that define what are allowable tags in an XHTML file

IMDB XML

The XML DeclarationThe 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

EncodingEverything we see on a computer is internally

represented as binary data

ASCII (American Standard Code for Information Interchange)

UNICODE

65 Uppercase A66 Uppercase B67 Uppercase C68 Uppercase D69 Uppercase E70 Uppercase F

41 Uppercase A42 Uppercase B43 Uppercase C44 Uppercase D45 Uppercase E46 Uppercase F

How do we translate the following? - 46, 41, 44, 45

The Root ElementA 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 <Title>

Elements <LocalTitle>28 Days Later</LocalTitle>

Opening tag <LocalTitle>Closing tag </LocalTitle>Data 28 Days Later

Attributes and ValuesAdded to elements to include additional data(Modified structure to illustrate attributes

and values)

Five Rules of XML1. Tag names are case sensitiveThis 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 XML2. 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 XML3. A nested tag pair cannot overlap another tag

Good Bad <Persons> <Person> <Name>Alex Palmer</Name> <Type>Actor</Type> <Role>Activist</Role> </Person>

<Persons> <Person> <Name>Alex Palmer</Name> <Type>Actor</Type> <Role>Activist</Person></Role>

Five Rules of XML4. 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 XML5. Every document must have a root element