示例：指定 ID 和 IDREF 指令

此示例与 指定 ELEMENTXSINIL 指令 示例几乎相同。 唯一的差别在于查询指定的是 ID 和 IDREF 指令。 这些指令将覆盖 和>OrderDetail< 元素中 <OrderHeader> SalesPersonID 属性的类型。 这会形成文档内链接。 您需要使用架构才能查看被覆盖的类型。 因此，该查询在 FOR XML 子句中指定 XMLDATA 选项来检索架构。

USE AdventureWorks2012;  
GO  
SELECT  1 as Tag,  
        0 as Parent,  
        SalesOrderID  as [OrderHeader!1!SalesOrderID!id],  
        OrderDate     as [OrderHeader!1!OrderDate],  
        CustomerID    as [OrderHeader!1!CustomerID],  
        NULL          as [SalesPerson!2!SalesPersonID],  
        NULL          as [OrderDetail!3!SalesOrderID!idref],  
        NULL          as [OrderDetail!3!LineTotal],  
        NULL          as [OrderDetail!3!ProductID],  
        NULL          as [OrderDetail!3!OrderQty]  
FROM   Sales.SalesOrderHeader  
WHERE  SalesOrderID=43659 or SalesOrderID=43661  
UNION ALL   
SELECT 2 as Tag,  
       1 as Parent,  
        SalesOrderID,   
        NULL,  
        NULL,  
        SalesPersonID,    
        NULL,           
        NULL,           
        NULL,  
        NULL           
FROM   Sales.SalesOrderHeader  
WHERE  SalesOrderID=43659 or SalesOrderID=43661  
UNION ALL  
SELECT 3 as Tag,  
       1 as Parent,  
        SOD.SalesOrderID,  
        NULL,  
        NULL,  
        SalesPersonID,  
        SOH.SalesOrderID,  
        LineTotal,  
        ProductID,  
        OrderQty     
FROM    Sales.SalesOrderHeader SOH,Sales.SalesOrderDetail SOD  
WHERE   SOH.SalesOrderID = SOD.SalesOrderID  
AND     (SOH.SalesOrderID=43659 or SOH.SalesOrderID=43661)  
ORDER BY [OrderHeader!1!SalesOrderID!id], [SalesPerson!2!SalesPersonID],  
         [OrderDetail!3!SalesOrderID!idref],[OrderDetail!3!LineTotal]  
FOR XML EXPLICIT, XMLDATA  

下面是部分结果： 请注意，在架构中，ID 和 IDREF 指令已覆盖 和><OrderDetail元素中 SalesOrderID 属性的<OrderHeader>数据类型。 如果删除这些指令，架构将返回这些属性的原始类型。

<Schema name="Schema1" xmlns="urn:schemas-microsoft-com:xml-data" xmlns:dt="urn:schemas-microsoft-com:datatypes">  
  <ElementType name="OrderHeader" content="mixed" model="open">  
    <AttributeType name="SalesOrderID" dt:type="id" />  
    <AttributeType name="OrderDate" dt:type="dateTime" />  
    <AttributeType name="CustomerID" dt:type="i4" />  
    <attribute type="SalesOrderID" />  
    <attribute type="OrderDate" />  
    <attribute type="CustomerID" />  
  </ElementType>  
  <ElementType name="SalesPerson" content="mixed" model="open">  
    <AttributeType name="SalesPersonID" dt:type="i4" />  
    <attribute type="SalesPersonID" />  
  </ElementType>  
  <ElementType name="OrderDetail" content="mixed" model="open">  
    <AttributeType name="SalesOrderID" dt:type="idref" />  
    <AttributeType name="LineTotal" dt:type="number" />  
    <AttributeType name="ProductID" dt:type="i4" />  
    <AttributeType name="OrderQty" dt:type="i2" />  
    <attribute type="SalesOrderID" />  
    <attribute type="LineTotal" />  
    <attribute type="ProductID" />  
    <attribute type="OrderQty" />  
  </ElementType>  
</Schema>  
<OrderHeader xmlns="x-schema:#Schema1" SalesOrderID="43659" OrderDate="2001-07-01T00:00:00" CustomerID="676">  
  <SalesPerson SalesPersonID="279" />  
  <OrderDetail SalesOrderID="43659" LineTotal="10.373000" ProductID="712" OrderQty="2" />  
  ...  
</OrderHeader>  
...  

另请参阅

将 EXPLICIT 模式与 FOR XML 一起使用