利用关联来过滤MOSS中的BDC数据 (1)

BDC允许我们为特定的LOB(line-of-business)系统定义多个实体。而且，在元数据文件中，我们可以创建关联来定义实体间的层次关系。如，有两个实体的定义，customers和orders。我们可以创建关联将customer实体直接与order实体联系在一起。这样就可以允许用户在MOSS中创建并使用主子(master-child)行为。

本文将向大家介绍如何在MOSS中利用关联来过滤BDC数据。大家继续使用之前在介绍BDC实体创建的文章中使用的元数据文件。

1. 在元数据文件中添加Sales Order实体
   
   在已有的Customer实体元素下面添加下列内容。该XML定义了一个新的实体，名为SalesOrder。
   
   <Entity Name="SalesOrder">
      <Properties>
         <Property Name="Title" Type="System.String">salesordernumber</Property>
      </Properties>
      <Identifiers>
         <Identifier Name="SalesOrderID" TypeName="System.Int32"/>
      </Identifiers>
      <Methods>
         <Method Name="GetSalesOrders">
            <Properties>
               <Property Name="RdbCommandText" Type="System.String">
                  SELECT
                     soh.salesorderid,
                     soh.orderdate,
                     soh.shipdate,
                     soh.status,
                     soh.salesordernumber,
                     soh.customerid
                  FROM
                     sales.salesorderheader soh
                     inner join sales.customer c
                     on soh.customerid = c.customerid
                  WHERE
                     c.customertype = 'i'
                     AND (soh.salesorderid &gt; @minSalesOrderID AND 
                          soh.salesorderid &lt; @maxSalesOrderID)
               </Property>
               <Property Name="RdbCommandType" Type="System.String">Text</Property>
            </Properties>
            <Parameters>
               <Parameter Direction="In" Name="@minSalesOrderID">
                     <TypeDescriptor TypeName="System.Int32" Name="SalesOrderID" 
                     IdentifierName="SalesOrderID">
                     <DefaultValues>
                        <DefaultValue MethodInstanceName=
                        "SalesOrderFinderInstance" Type="System.Int32">0
                        </DefaultValue>
                        <DefaultValue MethodInstanceName=
                        "SalesOrderSpecificFinderInstance" Type="System.Int32">0
                        </DefaultValue>
                     </DefaultValues>
                  </TypeDescriptor>
               </Parameter>
               <Parameter Direction="In" Name="@maxSalesOrderID">
                  <TypeDescriptor TypeName="System.Int32" Name="SalesOrderID" 
                  IdentifierName="SalesOrderID">
                     <DefaultValues>
                        <DefaultValue MethodInstanceName=
                        "SalesOrderFinderInstance" Type="System.Int32">
                        9999999</DefaultValue>
                        <DefaultValue MethodInstanceName=
                        "SalesOrderSpecificFinderInstance" Type="System.Int32">
                        9999999</DefaultValue>
                     </DefaultValues>
                  </TypeDescriptor>
               </Parameter>
               <Parameter Direction="Return" Name="SalesOrders">
                  <TypeDescriptor TypeName="System.Data.IDataReader, System.Data, 
                  Version=2.0.3600.0, Culture=neutral, PublicKeyToken=
                  b77a5c561934e089" IsCollection="true" Name="SalesOrderDataReader">
                     <TypeDescriptors>
                        <TypeDescriptor TypeName="System.Data.IDataRecord, System.Data, 
                        Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" 
                        Name="SalesOrderDataRecord">
                           <TypeDescriptors>
                              <TypeDescriptor TypeName="System.Int32" IdentifierName=
                              "SalesOrderID" Name="SalesOrderID" />
                              <TypeDescriptor TypeName="System.DateTime"  Name="orderdate" />
                              <TypeDescriptor TypeName="System.DateTime" Name="shipdate" />
                              <TypeDescriptor TypeName="System.String" Name="status" />
                              <TypeDescriptor TypeName="System.String" Name="salesordernumber" />
                              <TypeDescriptor TypeName="System.Int32" Name="customerid" />
                              </TypeDescriptors>
                        </TypeDescriptor>
                     </TypeDescriptors>
                  </TypeDescriptor>
               </Parameter>
            </Parameters>
            <MethodInstances>
               <MethodInstance Name="SalesOrderFinderInstance" Type="Finder" 
               ReturnParameterName="SalesOrders" />
               <MethodInstance Name="SalesOrderSpecificFinderInstance" Type="SpecificFinder" 
               ReturnParameterName="SalesOrders" />
            </MethodInstances>
         </Method>
      </Methods>
   </Entity>