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XML: New Version Edit

Extensible Markup Language (XML) is general purpose markup language derived from Standard Generalized Markup Language (SGML) that looks over the html standard. XML is a less complicated version on SGML and was fromed by Sun Microsystems Jon Bosak. This makes the language less complex and easier to understand than SGML. XML is considered extensible because it does not have the limitations that HTML has. Instead of being a predefined markup language like HTML, XML is a metalanguage. Meaning it’s a language to represent and manipulate data elements.

XML is good for infromation identification, infromation storage, infromation structure, publishing, messaging and data exchange and web services. XML is used as a language for data exchange across the internet for web services. Asynchronous JavaScript and XML (AJAX) is an example and it’s a web development technique to make web pages more interactive. It actually “pre-fetches the required data asynchronously from an XML-backed data-store”. XML is a textual based language it can be used across many platforms. This makes it very portable. XML is also used for data encapsulation. This means it is used to put an envelope around data to transfer it to other places.

HOW TO USE XML:Edit

XML is used everywhere in the world. A primary reason for this: data storage simplification.


Data Separated

If you need to show dynamic data in the HTML document, it will take a sustainable amount of work to edit the HTML each time changes in the data occur.

XML lets you store data in separate files. Any changes in the underlying data will not require changes in the HTML. With this, you can concentrate on the layout and appearance using HTML.


Data Sharing

In modern society, databases always contain data that is incompatible with other databases.

XML uses plain text to store data. By doing this, XML is stored using a software/hardware independent method.

This creates a much simpler way to create data that can shared by many different application providers.


Data Transport

Over the internet developers can exchange data over the internet. This is an incredibly time consuming activity; hours, days months, etc.

If you want to reduce complexity of the data, switch to XML. The reason XML reduces complexity is because the data can be read by these incompatible applications.


Platform Changes

When switching or upgrading platforms (either hardware or software), you better be prepared to spend a lot of time and money. When large amounts of data have to be converted, there is a good chance that incompatible data will be lost.

XML is much easier to expand or upgrade to new browsers, applications, operating systems, with losing data. The reason this is much easier is because XML stores its data in a text format, making it much easier to read.


Availability

XML and HTML also make it easier for applications to access your data. Many different applications can do this.

Handheld computers, voice machines, news feeds and much more ask that XML be the primary language you use. Their reasoning: Because XML data is available to all of these. This is an important part of XML because people with disabilities use these machines.

Other Uses for XML: Edit

XML has changed the way the world works because it has provided a universal language that people from every country understand all over the world. This enabling of collaboration has inspired some very talented people to develop some technologies that have changed the internet as we know it but so much more!

  -RSS for developing Really Simple Syndication feeds
  -XML as a file Database
  -WSDL for developing web services 
  -WAP and WML developing for handheld devices 
  -XHTML a new version of the HTML language 

People all over the world use these services with or without knowing it on a daily basis. It is important to become familar with atleast the concept of XML because it is extremely powerful and as it has been shown in the past, to be limited only by creativity.

The building blocks: Edit

An XML document has different parts. These parts are called elements and usually the XML document consists of one or more different elements. An XML document can have a body element. Each element has two tags, an opening tag and a closing tag. For example the opening tag for a body element would be <body> and the closing tag would look like this </body>. Notice that the closing tag has a forward slash infront of the element name, unlike the opening tag. Most elements will have text inbetween the opening and closing tag, but some may not have any text to add non-textual content to an XML document.


Example: Edit

Below is an example of XML used to store information about compact discs.

<?xml version="1.0" encoding="ISO-8859-1" ?>
<CATALOG>
  <CD>
     <TITLE>Empire Burlesque</TITLE>
     <ARTIST>Bob Dylan</ARTIST>
     <COUNTRY>USA</COUNTRY>
     <COMPANY>Columbia</COMPANY>
     <PRICE>10.90</PRICE>
     <YEAR>1985</YEAR>
  </CD>
  <CD>
     <TITLE>Hotel California</TITLE>
     <ARTIST>The Eagles</ARTIST>
     <COUNTRY>USA</COUNTRY>
     <COMPANY>Criteria Studios and Record Plant Studios</COMPANY>
     <PRICE>10.90</PRICE>
     <YEAR>1976</YEAR>
  </CD>
<CATALOG>


Sources Flynn, P (Ed.), The XML FAQ v.4.54, Cork, 2006-06-01, http://xml.silmaril.ie/ --Constantine411 03:18, 17 October 2006 (UTC)

Eckstein, Robert and Michel Casabianca. “XML Pocket Reference” O’Reily and Associates, Inc. 2001.

http://www.w3schools.com/xml/xml_usedfor.asp

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