Presented By :-Kunal Roy

Subranjoy Debnath

XML TECHNOLOGY

Contents :- Introduction to XML How XML Works Infrastructure of XML Where XML is Used Advantages & Disadvantages of

XML

eXtensible Markup Language

File extension : .xml MIME type : application/xml ,

text/xml(deprecated)

Uniform Type : public.xmlIdentifier

Type of format : Markup Language

Extended form : SGML

What Is XML ?

eXtensible Markup Language (XML) Markup Language for documents

containing structured information Defined by four specifications:

XML , the eXtensible Markup Language XLL , the eXtensible Linking Language XSL , the eXtensible Style Language XUA , the XML User Agent

XML…

Based on Standard Generalized Markup Language (SGML) ISO-8879 .

Version 1.0 introduced by World Wide Web Consortium (W3C) in 1998 .

Bridge for data exchange on the Web . XML is cross platform , hardware &

software independent language . An XML document is attached

to a Document Type Definition

which describes its structure .

ComparisonsXML & HTML

XML HTML Extensible set of

tags Content oriented Standard Data

infrastructure Allows multiple

output forms

Fixed set of tags Presentation

oriented No data

validation capabilities

Single presentation

Processing Instruction :XML document usually begins with the

Processing Instruction(PI).Example of a PI statement -

<?xml version=“1.0” encoding=“UTF-8”?>

Tags :Tags are used to identifying data.Data is marked-up by using tags.Opening & Closing angular bracket(<>) are

enclose the name of the Tags. <NAME>Rajesh Mittal</NAME>

Elements :Basic units used to identify and describe data .Elements are represented by using tags .

XML document must have a root element . Content :

Example of a content – <BOOKNAME> The Painted

House</BOOKNAME>Information represented by the element is

referred as the content of that element .Contents are further divided into :-

Element Content Data ContentMixed Content

Attributes :Attributes provide additional information .Elements can have one or more attributes .Attribute consists of a name value pair .

Comments :It is a good programming practice .Example of comment entry –<!– PRODUCTDATA is the root element -->Comments are used to explain the code .

Document Type Definition (DTD) :DTD defines the structure of the content of an

XML document .It specifies the elements along with their

attributes that can be present in the XML document .

Types of DTD – Internal DTD External DTD

XML Schema : It is used to define the structure of XML document. It defines the list if elements & attributes . An XML Schema also specifies the order in which

the elements appear & also their data types .

Feature DTD Schema

Syntax Non – XML syntax XML syntax

Namespaces No Support Supports Namespaces

Inheritance No Support Supports Inheritance

Data Type Support Limited to String format

Wide range of data types including , string , real , etc.

Applicability Wide spread due to many years of practical application

Comparatively New

XML is used to exchange structured documents over internet .

XML can be used as a format to transfer structured data between heterogeneous systems as it is platform independent .

XML can be used effectively with applications like Java .

XML can be used to create new languages e.g. WML , VRML .

Advantages :- It is based on International Standards . It has User Specific Vocabulary , i.e. user

defined tags can be created .The Hierarchical Structure is suitable for

almost all types of documents . It is platform independent , thus relatively

immune to changes in technology .

XML provides the feature of conditional formatting of a document which HTML does not provide .

Forward & backward compatibility are easy to maintain despite the changes in DTD or Schema .

Disadvantages :-Repetition : In XML every element and

attribute name for every element and attribute instance has to be repeated .

External References : The biggest performance risk for XML comes from the fact that it can include external files .