Mark attribute as required : Attribute « XML Schema « XML Tutorial

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3. Attribute

File: Schema.xsd


<?xml version="1.0" encoding="UTF-8"?>
<xs:schema 
  targetNamespace="http://www.oreilly.com/xslt" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema" 
  xmlns="http://www.oreilly.com/xslt">
  
  <xs:element name="part">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="name" minOccurs="1" maxOccurs="1"/>
      </xs:sequence>
      <xs:attribute name="part-id" type="xs:ID" use="required"/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name="name" type="xs:string"/>
  
  <xs:element name="partref">
    <xs:complexType>
      <xs:attribute name="refid" type="xs:IDREF" use="required"/>
    </xs:complexType>
  </xs:element>
</xs:schema>