What is XML extensible markup language used for?

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  • What is XML?
  • XML Does Not DO Anything
  • The Difference Between XML and HTML
  • XML Does Not Use Predefined Tags
  • XML is Extensible
  • Old Version
  • New Version
  • XML Simplifies Things
  • XML is a W3C Recommendation
  • What is XML extension used for?
  • What does extensible markup language XML mean?
  • What is XML with example?
  • Why is XML useful?

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What is XML?

XML stands for extensible markup language. A markup language is a set of codes, or tags, that describes the text in a digital document. The most famous markup language is hypertext markup language (HTML), which is used to format Web pages. XML, a more flexible cousin of HTML, makes it possible to conduct complex business over the Internet.

What are XML’s advantages over HTML?

Whereas HTML tells a browser application how a document should look, XML describes what’s in the document. In other words, XML is concerned with how information is organized, not how it is displayed. (XML formatting is done through separate style sheets.)

To illustrate, consider the following HTML tags: the command

signals a paragraph and word translates into word. The HTML tags are fixed; every site developer uses the same tags to do the same things. XML, by contrast, lets you create your own tags to label the meaning or use of data. So if you’re using XML to describe a widget you’re selling, your tags might look like this: $100” SKU=“555432” dealer=“Widgets Incorporated”>.

XML’s flexibility has many benefits. It lets you transfer data among corporate databases and Web sites without losing crucial descriptive information. It lets you automatically customize the presentation of data rather than display the same page to all comers. And it makes searches more efficient because search engines can sort through precise tags rather than long pages of text.

What are the business applications of XML?

Because XML brings sophisticated data coding to Web sites, it helps companies integrate their information flows. By creating a single set of XML tags for all corporate data, information can be shared seamlessly among Web sites, databases, and other back-end systems. But the revolutionary power of XML lies in supporting transactions between businesses. When a company sells a good or service to another company, a great deal of information needs to be exchanged—about prices, terms, specifications, delivery schedules, and so on. HTML’s one-size-fits-all nature makes such exchanges difficult, if not impossible, over the Internet. With XML, all the necessary information can be shared electronically, allowing complex deals to be closed without any human intervention. That’s why business-to-business Web markets, such as those run by Ariba and Commerce One, already rely on XML to automatically match buyers and sellers. In the not-too-distant future, your company may be judged by the content of its XML tags.

But if individual companies create their own tags, how will they share information with one another?

That’s the risk of flexibility. Without a standardized syntax, one company may create unique tags that are unrecognizable to its suppliers and buyers. To reduce that danger, many XML dictionaries are being created in fields like finance, mathematics, chemicals, and e-commerce. Embedded in XML, these dictionaries standardize tag definitions. On Wall Street, for example, JP Morgan and PricewaterhouseCoopers recently proposed FpML, a dictionary that would standardize the XML tags for foreign currency exchange and other financial transactions. Similar efforts are under way in other industries.

A version of this article appeared in the July–August 2000 issue of Harvard Business Review.

XML is a software- and hardware-independent tool for storing and transporting data.

What is XML?

• XML stands for eXtensible Markup Language
• XML is a markup language much like HTML
• XML was designed to store and transport data
• XML was designed to be self-descriptive
• XML is a W3C Recommendation

XML Does Not DO Anything

Maybe it is a little hard to understand, but XML does not DO anything.

This note is a note to Tove from Jani, stored as XML:

  Tove
  Jani
  Reminder
  Don't forget me this weekend!

The XML above is quite self-descriptive:

• It has sender information
• It has receiver information
• It has a heading
• It has a message body

But still, the XML above does not DO anything. XML is just information wrapped in tags.

Someone must write a piece of software to send, receive, store, or display it:

Note

To: Tove

From: Jani

Reminder

Don't forget me this weekend!

The Difference Between XML and HTML

XML and HTML were designed with different goals:

• XML was designed to carry data - with focus on what data is
• HTML was designed to display data - with focus on how data looks
• XML tags are not predefined like HTML tags are

XML Does Not Use Predefined Tags

The XML language has no predefined tags.

The tags in the example above (like and ) are not defined in any XML standard. These tags are "invented" by the author of the XML document.

HTML works with predefined tags like

,

, , etc.

With XML, the author must define both the tags and the document structure.

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XML is Extensible

Most XML applications will work as expected even if new data is added (or removed).

Imagine an application designed to display the original version of note.xml ( ).

Then imagine a newer version of note.xml with added and elements, and a removed .

The way XML is constructed, older version of the application can still work:

  2015-09-01
  08:30
  Tove
  Jani
  Don't forget me this weekend!

Old Version

Note

To: Tove

From: Jani

Reminder

Don't forget me this weekend!

New Version

Note

To: Tove

From: Jani

Date: 2015-09-01 08:30

Don't forget me this weekend!

---

XML Simplifies Things

• XML simplifies data sharing
• XML simplifies data transport
• XML simplifies platform changes
• XML simplifies data availability

Many computer systems contain data in incompatible formats. Exchanging data between incompatible systems (or upgraded systems) is a time-consuming task for web developers. Large amounts of data must be converted, and incompatible data is often lost.

XML stores data in plain text format. This provides a software- and hardware-independent way of storing, transporting, and sharing data.

XML also makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data.

With XML, data can be available to all kinds of "reading machines" like people, computers, voice machines, news feeds, etc.

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XML is a W3C Recommendation

XML became a W3C Recommendation as early as in February 1998.

What is XML extension used for?

To summarize: An XML file is a file used to store data in the form of hierarchical elements. Data stored in XML files can be read by computer programs with the help of custom tags, which indicate the type of element.

What does extensible markup language XML mean?

XML (Extensible Markup Language) is a markup language similar to HTML, but without predefined tags to use. Instead, you define your own tags designed specifically for your needs. This is a powerful way to store data in a format that can be stored, searched, and shared.

What is XML with example?

XML stands for Extensible Markup Language. It is a text-based markup language derived from Standard Generalized Markup Language (SGML). XML tags identify the data and are used to store and organize the data, rather than specifying how to display it like HTML tags, which are used to display the data.

Why is XML useful?

General applications: XML provides a standard method to access information, making it easier for applications and devices of all kinds to use, store, transmit, and display data.

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