eXtensible Markup Language

eXtensible Markup Language

Prepared by Aditya Raj

eXtensible Stylesheet Language


XML | XML Schema | XML Structure | Basic Coding

What is XML?

Why to choose XML?

What is XML schema?

XML structure

Basics of XML coding

By end of this presentation, we will be able to know



XML is a general purpose, cross platform, markup language, that is supported by W3C (World Wide Consortium) and is used for communication between systems on different or same platform.

XML is used to describe and store data and should not be misunderstood with a programming language.

The good news is XML tags are not predefined and you can define your own tags

What is XML?



XML stores the data in a structured manner

Data can just not be stored but also it can be described to any extent

Systems using XML are considered to be highly scalable

Structural changes to data can be managed easily

Easy to learn and easy to use

In machine and human readable format

XML is FREE

Why to choose XML?



XML Schema are guidelines or format for describing data using XML.

In order to use XML data it must conform to these standards.

The oldest schema format for XML is DTD (Document Type Definition) but it is now obsolete as:

It has no support for new features

Certain aspects of data cannot be described using DTD

XSD (XML Schema Definition) is one of the most powerful XML schemas and is commonly used.

They allow detailed constraints on an XML document’s logical structure.

Finally it depends on the system requirement and data type that which XML schema should be used.

What is a XML schema?



XML structure

Data Structure of XML can best described as a hierarchy of information like a tree.

A hierarchy structure has a parent, child and a sibling relationship with other entities.

In XML every entity at any level can have its own properties.

Siblings

Parent

Child

Name

Age

Gender

Properties



Address Book

Contact

Email Numbers Address

Mobile Home Phone StateCountryStreet Address

Contact

Email Numbers Address

Mobile Home Phone StateCountryStreet Address

Basic XML coding

<addressBook>

<contact fName="john" lName="“ nickName="Johny" dob="1st January 1990">

</contact>

<email>[email protected]</email>

<numbers>

</numbers>

<address>

</address>

<streetAddress>123, x block, Vasant Vihar </streetAddress><country>India</country>

<state>New Delhi</state><zipCode>110057</zipCode>

<mobile>9988998899</mobile><mobile>9988998800</mobile><homeNumber>01126150000</homeNumber>

<?xml version="1.0" encoding="ISO-8859-1"?>

</addressBook>


XSL | XSLT | XPath | Basic Coding

What is XSL?

What is XSLT?

What is XPath?

Example

Now we are about to know:



What is XSL?

XSL is developed by W3C to facilitate need of style sheet to display formatted information stored in XML like CSS is there for HTML.

XSL is like a tripod supported by three legs called:

XSLT (eXtensible Stylesheet Language Transformation)

XPath (XML Path Language)

XSL-FO (eXtensible Stylesheet Language Formatting Objects)

XSL is classified under two operations, formatting and transformation. XSLT describes the transformation of XSL and XSL-FO is used for formatting but practically they are same.



What is XSLT?

XSLT (eXtensible Stylesheet Language Transformation) transforms XML data using XSL to form a well formatted document, usually HTML.

About XSLT processorsOne of the most simplest way of XSLT is client side, so when a XML document is requested by client application, it refers to its related XSL file and the transformation takes place at the client side.

This method is not recommended due to compatibility concerns as it is highly possible that client might not support XML transformation or may not support the latest features.

Hence it is recommended to perform the transformation at the server level and pass the resulted data to the client, avoiding any compatibility concerns.

There are several standalone software and libraries available for performing transformation. Like for ruby on rails we have library named XSLT and for Windows XP we have MSXML 3.



What is XPath?XPath (XML Path Language) is used to navigate the data inside XML document to find required information and it is also used for computing values, in simple words XPath is a small query language.

XPath expressions

Expression Description

nodename Selects all child nodes of the node

/ Selects from the root node

// Selects nodes in the document from the current node that match the selection no matter where they are

. Selects the current node

.. Selects the parent of the current node

@ Selects attributes

nodename/* Selects all child nodes of the node

//* Selects all nodes in the document

nodename/node[1] Selects first child element of the node



Now lets make XSL for the XML we made before !!

Thanks…

Technology

eXtensible Markup Language