• 项目

使用 ADO 执行 Updategram (SQLXML 4.0)

该 Microsoft Visual Basic 应用程序使用 ADO 建立与 Microsoft SQL Server 实例的连接，并执行 updategram。updategram 更新特定雇员的姓氏。此示例使用 AdventureWorks2008R2 示例数据库。

在此示例应用程序中：

  • conn 对象 (ADODB.Connection) 建立与特定服务器计算机上正在运行的 SQL Server 实例的连接。

  • 在已建立的连接上执行 cmd 对象 (ADODB.Command)。

  • 将命令方言设置为 DBGUID_MSSQLXML。

  • 将 updategram 复制到命令流 (strmIn)。

  • 将该命令的输出流设置为 StrmOut 对象 (ADODB.Stream) 以便接收任何返回的数据。

  • 最后，执行该命令 (updategram)。

以下是示例代码：

Private Sub Form_Load()

  Dim cmd As New ADODB.Command
  Dim conn As New ADODB.Connection
  Dim strmIn As New ADODB.Stream
  Dim strmOut As New ADODB.Stream
  Dim SQLxml As String

  ' Open a connection to the instance of SQL Server.
  conn.Provider = "SQLOLEDB"
  conn.Open "server=(local); database=AdventureWorks2008R2; Integrated Security=SSPI; "
  conn.Properties("SQLXML Version") = "SQLXML.4.0"
  Set cmd.ActiveConnection = conn

  ' Build the command string in the form of an XML template.
    SQLxml = "<ROOT xmlns:updg='urn:schemas-microsoft-com:xml-updategram' >"
    SQLxml = SQLxml & "  <updg:sync updg:nullvalue='IsNULL'>"
    SQLxml = SQLxml & "    <updg:before>"
    SQLxml = SQLxml & "       <Person.Person BusinessEntityID='64' Title='IsNULL'/>"
    SQLxml = SQLxml & "    </updg:before>"
    SQLxml = SQLxml & "    <updg:after>"
    SQLxml = SQLxml & "       <Person.Person BusinessEntityID='64' Title='Mr.'/>"
    SQLxml = SQLxml & "    </updg:after>"
    SQLxml = SQLxml & "  </updg:sync>"
    SQLxml = SQLxml & "</ROOT>"

  ' Set the command dialect to DBGUID_MSSQLXML.
  cmd.Dialect = "{5d531cb2-e6ed-11d2-b252-00c04f681b71}"

  ' Open the command stream and write our template to it.
  strmIn.Open
  strmIn.WriteText SQLxml
  strmIn.Position = 0

  Set cmd.CommandStream = strmIn

  ' Execute the command, open the return stream, and read the result.
  strmOut.Open
  strmOut.LineSeparator = adCRLF
  cmd.Properties("Output Stream").Value = strmOut
  cmd.Properties("Output Encoding").Value = "UTF-8"
  cmd.Execute , , adExecuteStream
  strmOut.Position = 0
  Debug.Print strmOut.ReadText
  strmOut.Close
  strmIn.Close

End Sub
注意注意

如果从 ADO 使用 SQLXML 执行指定 XSD 架构的 updategram，必须在连接对象上将“SQLXML Version”属性设置为“SQLXML.4.0”，如下面的示例代码行所示：

conn.Properties("SQLXML Version") = "SQLXML.4.0"

为 Updategram 指定映射架构

本示例中演示如何在 updategram 中指定和使用映射架构。

将以下 XSD 架构 (EmpSchema.xml) 保存到磁盘，并确保将代码中指定的路径更新为磁盘上映射架构的位置。代码假定该架构保存在 C: 驱动器的 Schemas 文件夹中。

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:sql="urn:schemas-microsoft-com:mapping-schema">
  <xsd:element name="Contact" sql:relation="Person.Person" >
   <xsd:complexType>
        <xsd:attribute name="CID"  
                       sql:field="BusinessEntityID" 
                       type="xsd:string" /> 
        <xsd:attribute name="MName"  
                       sql:field="MiddleName"  
                       type="xsd:string" />
    </xsd:complexType>
  </xsd:element>
</xsd:schema>

可以指定 XSD 和 XDR 架构，以下是等效的 XDR 架构：

<?xml version="1.0" ?>
   <Schema xmlns="urn:schemas-microsoft-com:xml-data" 
         xmlns:dt="urn:schemas-microsoft-com:datatypes" 
         xmlns:sql="urn:schemas-microsoft-com:xml-sql">
     <ElementType name="Contact" sql:relation="Person.Person" >
       <AttributeType name="CID" />
       <AttributeType name="MName" />

       <attribute type="CID" sql:field="BusinessEntityID" />
       <attribute type="MName" sql:field="MiddleName" />
     </ElementType>
   </Schema>

以下是执行具有关联映射架构的 updategram 的 Visual Basic 代码。该 updategram 更新 Person.Person 表中第 1 个联系人的中间名。

Private Sub Form_Load()
    Dim cmd As New ADODB.Command
    Dim conn As New ADODB.Connection
    Dim strmIn As New ADODB.Stream
    Dim strmOut As New ADODB.Stream

    ' Open a connection to the SQL Server.
    conn.Provider = "SQLOLEDB"
    conn.Open "server=(local); database=AdventureWorks2008R2; Integrated Security='SSPI' ;"
    conn.Properties("SQLXML Version") = "SQLXML.4.0"
    Set cmd.ActiveConnection = conn
    
    ' Open the command stream and write the template to it.
    strmIn.Open
    strmIn.WriteText "<ROOT xmlns:updg='urn:schemas-microsoft-com:xml-updategram' >"
    strmIn.WriteText "  <updg:sync mapping-schema='C:\Schemas\EmpSchema.xml' >"
    strmIn.WriteText "      <updg:before>"
    strmIn.WriteText "          <Contact CID='1' />"
    strmIn.WriteText "      </updg:before>"
    strmIn.WriteText "      <updg:after>"
    strmIn.WriteText "          <Contact MName='M.'/>"
    strmIn.WriteText "      </updg:after>"
    strmIn.WriteText "  </updg:sync>"
    strmIn.WriteText "</ROOT>"
    
    ' Set the command dialect to XML.
    cmd.Dialect = "{5d531cb2-e6ed-11d2-b252-00c04f681b71}"
    strmIn.Position = 0
    Set cmd.CommandStream = strmIn
 
    ' Execute the command, open the return stream, and read the result.
    strmOut.Open
    strmOut.LineSeparator = adCRLF
    cmd.Properties("Output Stream").Value = strmOut
    cmd.Execute , , adExecuteStream
    strmOut.Position = 0
    Debug.Print strmOut.ReadText
    strmOut.Close
    strmIn.Close
    conn.Close
End Sub

传递参数

在以前提供的 Visual Basic 应用程序中，不能传递参数。在此应用程序中，BusinessEntityID 和 MiddleName 值作为参数化输入传递到 updategram。

Private Sub Form_Load()
  
  Dim cmd As New ADODB.Command
  Dim conn As New ADODB.Connection
  Dim strmIn As New ADODB.Stream
  Dim strmOut As New ADODB.Stream
  Dim InputBusinessEntityID As String
  Dim InputMiddleName As String

  InputBusinessEntityID = "1"
  InputMiddleName = "Q."

  ' Open a connection to the instance of SQL Server.
  conn.Provider = "SQLOLEDB"
  conn.Open "server=(local); database=AdventureWorks2008R2; Integrated Security=SSPI; "
  conn.Properties("SQLXML Version") = "SQLXML.4.0"
  Set cmd.ActiveConnection = conn

  ' Build the command string in the form of an XML template.
  SQLxml = "<ROOT xmlns:updg='urn:schemas-microsoft-com:xml-updategram' >"
  SQLxml = SQLxml & "<updg:header>"
  SQLxml = SQLxml & "<updg:param name='BusinessEntityID'/>"
  SQLxml = SQLxml & "<updg:param name='MiddleName' />"
  SQLxml = SQLxml & "</updg:header>"
  SQLxml = SQLxml & "<updg:sync >"
  SQLxml = SQLxml & " <updg:before>"
  SQLxml = SQLxml & "   <Person.Person BusinessEntityID='$BusinessEntityID' />"
  SQLxml = SQLxml & "</updg:before>"
  SQLxml = SQLxml & "<updg:after>"
  SQLxml = SQLxml & "<Person.Person MiddleName='$MiddleName' />"
  SQLxml = SQLxml & "</updg:after>"
  SQLxml = SQLxml & "</updg:sync>"
  SQLxml = SQLxml & "</ROOT>"

  ' Set the command dialect to XML.
  cmd.Dialect = "{5d531cb2-e6ed-11d2-b252-00c04f681b71}"

  ' Open the command stream and write the template to it.
  strmIn.Open
  strmIn.WriteText SQLxml
  strmIn.Position = 0

  Set cmd.CommandStream = strmIn

  ' Execute the command, open the return stream, and read the result.
  strmOut.Open
  strmOut.LineSeparator = adCRLF
  cmd.NamedParameters = True
  cmd.Parameters.Append cmd.CreateParameter("@BusinessEntityID", adBSTR, adParamInput, 1, InputBusinessEntityID)
  cmd.Parameters.Append cmd.CreateParameter("@MiddleName", adBSTR, adParamInput, 7, InputMiddleName)
  cmd.Properties("Output Stream").Value = strmOut
  cmd.Execute , , adExecuteStream
  strmOut.Position = 0
  Debug.Print strmOut.ReadText

End Sub