<?xml version='1.0'?>

<schema>

  <element name="product">
    <type content="elemOnly" order="seq">

      <element ref="product-group" minOccurs="1" maxOccurs="1"/>
      <element ref="product-inventory" minOccurs="1" maxOccurs="1"/>

      <attribute name="id" type="ID" minOccurs="1"/>
      <attribute name="name" type="string" minOccurs="1"/>
      <attribute name="price" type="real" minOccurs="1"/>

    </type>
  </element>

  <element name="product-group">
    <type content="empty">

      <attribute name="id" type="ID" minOccurs="1"/>
      <attribute name="name" type="string" minOccurs="1"/>

    </type>
  </element>

  <element name="product-inventory">
    <type content="empty">

      <attribute name="quantity" type="integer" minOccurs="1"/>

    </type>
  </element>

</schema>
