XML Namespaces

XML Namespaces 

• XML Namespaces avoid name conflicts in the XML document.
• Name conflict occurs when we found two tags with the same name.
• Name conflict can be resolved by using a prefix to the tag as shown below.
• <P:name>Ramu</P:name>   ------------->  name of the person.
• <A:name>Pappi</A:name> -------------> name of a dog.
• When a namespace is defined for an element, all child elements with the same prefix are associated
• with the same namespace.
• In order to maintain uniqueness in the namespaces, we should define the namespaces xmlns' is an attributed tag used to define a name space. We can define Namespace in two ways, 

• Defining at the time of usage,

<P:name xmlns:P="url">Ramu</P:name>

• Defining at the root tag, 

<root xmlns:P="url">

<P:name> Ramu</P:name>

</root>

Entity References

Some characters have a special meaning in XML. If you place a character like "<" inside an XML element, it will generate an error because the parser interprets it as the start of a new element. This will generate an XML error.

An example:

An XML tag: <message>if salary<2500 then </message>

Error Message: To avoid this error, replace the "<" character with an entity reference:

<message>if salary &lt; 2500 then </message>

There are five predefined entity references in XML: 

&It;	<	less than
&gt;	>	greater than
&amp;	&	ampersand
&apos;	‘	apostrophe
&quot;	“	quotation mark

Comments in XML

The syntax for writing comments in XML is similar to that of HTML.

<!-- This is a comment -->

With XML, White Space is Preserved.

HTML reduces multiple white space characters to a single white space:

HTML: Hello my name is Raju.

Output: Hello my name is Raju.

With XML, the white space in your document is not truncated.