XML/XML Schema/language

language type attribute

File: Data.xml
<?xml version="1.0"?>
<addr:address xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://www.wbex.ru Schema.xsd"
              xmlns:addr="http://www.wbex.ru"
              addr:language="en">
    
</addr:address>
File: Schema.xsd
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  targetNamespace="http://www.wbex.ru"
  xmlns:addr="http://www.wbex.ru"
  attributeFormDefault="qualified"
  elementFormDefault="qualified">
  
 <xsd:element name="address">
  <xsd:complexType mixed="true">
    <xsd:simpleContent>
      <xsd:extension base="xsd:string">
        <xsd:attributeGroup ref="addr:nationality"/>
      </xsd:extension>
    </xsd:simpleContent>
  </xsd:complexType>
 </xsd:element>
 <xsd:attributeGroup name="nationality">
    <xsd:attribute name="language" type="xsd:language"/>
 </xsd:attributeGroup>
</xsd:schema>

Restriction on xs:language

File: Data.xml
<?xml version="1.0"?>
<data xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://www.wbex.ru Schema.xsd"
              xmlns="http://www.wbex.ru"
              >
   en    
</data>
File: Schema.xsd
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  targetNamespace="http://www.wbex.ru" xmlns="http://www.wbex.ru"
  elementFormDefault="qualified">
    <xs:element name="data" type="supportedLanguages"/>

  <xs:simpleType name="supportedLanguages">
    <xs:restriction base="xs:language">
      <xs:enumeration value="en" />
      <xs:enumeration value="es" />
    </xs:restriction>
  </xs:simpleType>

</xs:schema>