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Executing a DiffGram by Using ADO (SQLXML 4.0)

  • 项目

This Microsoft Visual Basic application uses ADO to establish a connection to an instance of Microsoft SQL Server and then executes a DiffGram. In this application, the DiffGram and the XSD schema are stored in a file. The application loads the DiffGram from the specified file. You can use any of the DiffGrams (and the associated XSD schema) described in DiffGram Examples.

This is the process for the sample application:

  • The conn object (ADODB.Connection) establishes a connection to a running instance of SQL Server on a specific server.
  • The cmd object (ADODB.Command) executes on the established connection.
  • The command dialect is set to DBGUID_MSSQLXML.
  • The DiffGram is copied to the command stream (strmIn) from a file.
  • The command's output stream is set to the StrmOut object (ADODB.Stream) to receive any returned data.
  • When you are using the SQLOLEDB Provider, by default you will get the Microsoft SQLXML functionality provided by Sqlxmlx.dll. To use Sqlxml4.dll with the SQLOLEDB Provider, the SQLXML Version property must be set to SQLXML.4.0 on the SQLOLEDB Provider Connection object.
  • The command (DiffGram) is executed.

The following code is the sample application.

ms171859.note(zh-cn,SQL.90).gif注意：
In the code, you must provide the name of the instance of SQL Server in the connection string. 
Private Sub Command1_Click()
  Dim cmd As New ADODB.Command
  Dim conn As New ADODB.Connection
  Dim strmOut As New ADODB.Stream
  Dim strmIn As New ADODB.Stream
      
  'Open a connection to SQL Server.
  conn.Provider = "SQLOLEDB"
  conn.Open "server=SqlServerName; database=tempdb; Integrated Security=SSPI; "
  conn.Properties("SQLXML Version") = "SQLXML.4.0"
  Set cmd.ActiveConnection = conn
  strmIn.Open
  strmIn.Charset = "UTF-8"
  strmIn.LoadFromFile "C:\SomeFilePath\SampleDiffGram.xml"
  strmIn.Position = 0
  Set cmd.CommandStream = strmIn
    
  strmOut.Open
  cmd.Properties("Output Stream").Value = strmOut
  cmd.Properties("Output Encoding").Value = "UTF-8"
    
  cmd.Dialect = "{5d531cb2-e6ed-11d2-b252-00c04f681b71}"
  cmd.Properties("Mapping Schema") = "C:\SomeFilePath\SampleDiffGram.xml"
  cmd.Execute , , adExecuteStream
  strmOut.Position = 0
  Set cmd = Nothing
  strmOut.Charset = "UTF-8"
  strmOut.SaveToFile "C:\DropIt.txt", adSaveCreateOverWrite
  strmOut.Close
  Set strmOut = Nothing
  
End Sub

To test the DiffGram

  1. To a folder on your computer, copy any one of the DiffGrams and the corresponding XSD schema from one of the examples in DiffGram Examples.

  2. Open Visual Basic and create a Standard EXE project.

  3. Add these references to the project:

    Microsoft ActiveX Data Objects 2.8 Library

  4. In the Toolbox, click CommandButton, and then draw a button on the form.

  5. Double-click the button to edit the code, and add the application code that is provided in the topic.

  6. Edit the code to specify the DiffGram and XSD file names. Also edit the connection string as appropriate.

  7. Execute the application. The result of the execution depends on what DiffGram you are executing.