XML Attributes




XML Attributes

  • Attributes are the part of the Xml Elements. An Element contains multiple attributes. All are unique.
  • By the use of attributes we can add the information about the element.
  • XML attributes enhance the properties of the elements.
 Attributes

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Syntax

 <tag attibuteName=“attributeValue”>

Xml attribute Example

<author bookType="Classical">
//else
<author bookType=‘Classical’>

Attribute Vs Element

  • Metadata should be stored as attribute and data should be stored as element.
<author bookType="Classical">
		<name>Venkat</name>
		<nationality>Indian</nationality>
</author>

Attribute vs Sub-element or Elements

  • Attributes are part of markup, while sub elements are part of the basic document contents.

In the below code bookType is an attribute

<author bookType="Classical">

In the below code bookType is an element

<author>
     <bootType>Classical</bookType>
</author>
Attributes

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XML Attributes Rules

  • An attribute name must be appear once in the same start-tag or empty-element tag.
  • The value of the attributes within the quotation mark.
  • They used either single or double quotes.
 Attributes With Quotes

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  • Attributes must contain a value. Some HTML coders does provide the attribute name without a value or it will equal true. This is not allowed in XML.
  • The values must not contain direct or indirect entity references to external entities.
  • Using an Attribute-List Declaration , an attribute must be declared in the Document Type Definition (DTD).
 Attributes Value

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XML Tree Structure

Attributes With Quotes

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XML Attributes Drawbacks:

  • Attributes doesn’t have multiple values but child elements can have multiple values.
  • Attributes cannot contain tree structure but child element can.
  • Attributes are not easily expandable. If you want to change in attribute's vales in future, it may be complicated.
  • Attributes cannot describe structure but child elements can.
  • Attributes are more difficult to be manipulated by program code.
  • Attributes values are not easy to test against a DTD, which is used to define the legal elements of an XML document.

How XML is Presented ?

How XML is Presented

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