XSD - Attribute

Attribute represents the attribute of an XML element. XSD defines it as a simple type.

Syntax

<xs:attribute name = "attribute-name" type = "attribute-type"/>

attribute-name

Name of the Attribute. For example,

<xs:attribute name = "rollno" type = "xs:integer"/>

defines following rollno attribute which can be used in an XML element. For example

<student rollno = "393" />

attribute-type

Type of the Attribute. For example,

<xs:attribute name = "rollno" type = "xs:integer"/>

defines type of attribute as integer, rollno should have value of type int.

<student rollno = "393" />

Consider the following XML Element

<student rollno = "393" />

XSD declarations for rollno attribute will be as follows −

<xs:attribute name = "rollno" type = "xs:integer"/>

Attribute can have a default value assigned to it. Default value is used in case the attribute has no value.

<xs:attribute name = "grade" type = "xs:string" default = "NA" />

Attribute can have a fix value assigned. In case a fixed value is assigned, then the element can not have any value.

<xs:attribute name = "class" type = "xs:string" fixed = "1" />

Attributes are by default optional. But to make an attribute mandatory, "use" attribute can be used.

<xs:attribute name = "rollno" type = "xs:integer" use = "required"/>

xsd_simple_types.htm