XML Overview

Before you start learning XML, you should have basic idea about Website, Web Pages, Html and scripting like VBScrips or Java Scripts.

What is XML?

XML stands for Extensible Markup Language. We can also say that its text based markup language which derived from SGML (Standard Generalized Markup Language).

We can also say its similar like HTML as markup language. XML is designed to store data and you can display that data into web pages. There are limitations also there to store data into XML.

XML uses tags which are not predefined like HTML tags. You need to create your own tags and use to create XML. That means, it’s more like self describing. XML uses Document Type Definition to represent the data, it’s also called DTD.

Main difference between XML and HTML

XML and HTML are different in terms of their characteristics. They both have different goals and the way we use in application. We cannot replace XML with HTML. XML is used to describe the data, what data we want to store with that where HTML is used to represent the data in such a way we want either graphically or plain in web pages. In short, XML is describing the date and HTML is displaying the date.

It Does not do anything: XML doesn’t do anything which we want, but we can use with its limitation. Here, you can find few basic examples of how XML contents looks

What is Markup?

XML known as markup language which define some sort of rules to encode the XML document which can be easily understand by human or machine. So here, whatever information added in XML document, it can be placed with certain rules which define different label for information. We can also says its set of symbols which used to store information. See the following example how it looks, when we structure it with information.

Example 1

<?xml version="1.0" encoding="UTF-8"?>
<product>
<name>XML Tutorial Book</name>
<description>This book provide basic understanding of XML</description>
<price>$10.00</price>
</product>

In above example 1, we can say <product> <name> <description> <price> are tags or markup symbols. We can understand that it store only one product details like product name, description and product price. As mentioned above, we can define our tags which we want. Here, we can define n such a way which we can understand easily because its Markup Language.

Example 2

<?xml version="1.0" encoding="UTF-8"?>
<students>
<student>
<firstname>John</firstname>
<lastname>Turner</lastname>
<gender>Male</gender>
<age>10 Years</age>
<class>5th</class>
</student>
<student>
<firstname>Aidan</firstname>
<lastname>Walls</lastname>
<gender>Male</gender>
<age>12 Years</age>
<class>7th</class>
</student>
<student>
<firstname>Martyn</firstname>
<lastname>Hills</lastname>
<gender>Male</gender>
<age>13 Years</age>
<class>8th</class>
</student>
<student>
<firstname>Jeremy</firstname>
<lastname>Coester</lastname>
<gender>Male</gender>
<age>9 Years</age>
<class>4th</class>
</student>
</students>

In above Example 2, we can understand its more complex. It stores multiple students information. For example, tag “student” defined multiple time with its sub section, that means, it store multiple student information like that way.

There are few features of XML which are very important and it help in such systems.

  • Extensible: It allow you to create or define your own tags which you can use easily in your application or system.
  • It store data, doesn’t display data: XML is used to store and transform the data, it does not used to display any data.
  • Open Standard: XML does not follow any standard like HTML follow, you can define your own structure for XML to store data, that’s why it’s called Open Standard.

Where we can use XML?

There are various options where we can use XML.

  • XML is used to store and arrange the day in your designed way. You can even customize it the way you want it to structure.
  • XML is used to transform the data between application and organization.
  • XML is used as portable database to manage data in organization or in system.
  • XML can be merged with style sheet (XSD) in such way to represent data in web pages.
  • XML is used as back end in application and display the data into HTML.

Keep in mind, XML is not a programming language.

XML doesn’t perform any programming task like writing set of logic and algorithms to perform an action or calculate something. Programming is more about logical behaviour with computer. It calculates or performs any defined action and represents set of outputs. But, in computer, programming is used to read and write XML document.

Future about XML in website development

Now a days, XML can be used in many ways to store and transform information with system and organization. Main benefit of XML is how quickly set of rules and symbols for XML has been developed. And, many web and software development organizations have adopted easily to develop large number of website and software applications. People believe that XML will be having same important like HTML which is foundation for website development. XML will be used to transform huge data and manage it easily on website in future. Let’s understand more about XML in coming chapters.