XML Schema is an XML-based replacement for DTDs.
XML Schema describes the structure of an XML document.
The XML Schema language can also be referenced as XSD (XML Schema Definition).
XSD attributes syntax
Simple elements cannot have attributes. If an element has attributes, it is treated as a composite type. But the properties themselves are always declared as simple types.
XSD attributes example
In the following example, the default value is "EN":
<xs:attribute name="lang" type="xs: string" default="EN"/>
Fixed values are also automatically assigned to elements, and you cannot specify another value.
In the following example, the fixed value is "EN":
<xs:attribute name="lang" type= "xs:string" fixed="EN"/>