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<?xml version="1.0" encoding="ISO-8859-1"?>
<refentry id="MS-A-3a">
  <refmeta>
    <refentrytitle>Using Annotated XSD Schemas for Creating XML Views</refentrytitle>
    <refmiscinfo>tutorial</refmiscinfo>
  </refmeta>
  <refnamediv>
    <refname></refname>
    <refpurpose>Using sql:relationship to Specify Relationship on an attribute</refpurpose>
  </refnamediv>

<refsect1 id="MS-A-3aa">
<title>Example.</title>
<para>
The schema in this example includes a &apos;Customer&apos; element with &apos;CustomerID&apos; and 
&apos;ContactName&apos; child 
elements and an OrderIDList attribute of IDREFS type. The &apos;Customer&apos; element maps to the Customers table. 
By default, the scope of this mapping applies to all the child elements or attributes unless sql:relation 
is specified on the child element or attribute, in which case, the appropriate primary-key/foreign-key 
relationship must be defined using the &apos;relationship&apos; element. And the child element or attribute, 
which specifies the different table using the relation annotation, must also specify the relationship annotation.
</para>
<programlisting><![CDATA[
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:sql="urn:schemas-microsoft-com:mapping-schema">
<xsd:annotation>
  <xsd:appinfo>
    <sql:relationship name="CustOrders"
          parent="Demo.demo.Customers"
          parent-key="CustomerID"
          child="Demo.demo.Orders"
          child-key="CustomerID" />
     </xsd:appinfo>
</xsd:annotation>

  <xsd:element name="Customer" sql:relation="Demo.demo.Customers" type="CustomerType" />
   <xsd:complexType name="CustomerType" >
     <xsd:sequence>
        <xsd:element name="ContactName"  type="xsd:string" />
        <xsd:element name="CompanyName"  type="xsd:string" />
        <xsd:element name="City"  type="xsd:string" />
     </xsd:sequence>
     <xsd:attribute name="OrderIDList" 
                     type="xsd:IDREFS" 
                     sql:relation="Demo.demo.Orders" 
                     sql:field="OrderID"
                     sql:relationship="CustOrders" >
        </xsd:attribute>
     <xsd:attribute name="CustomerID"   type="xsd:string" /> 
    </xsd:complexType>
</xsd:schema>
]]></programlisting>
<para>Let the schema is written to the file &apos;Cust_Order_attr.xsd&apos;, then after loading this file by 
<function>xml_load_mapping_schema_decl</function> function, the first example will produce a result for the XPath query:
</para>
<programlisting><![CDATA[
XPATH [__view 'Cust_Order_attr'] /Customer[@CustomerID="QUEEN"]
]]></programlisting>
<para>
the second example will produce a result for the XQuery query:
</para>
<programlisting><![CDATA[
select xquery_eval('<doc>{for $r in xmlview("Cust_Order_attr")/*[@CustomerID="QUEEN"] return $r}</doc>', xtree_doc('<q/>')); ]]>
</programlisting>

</refsect1>
</refentry>
