Executing an Updategram by Using ADO (SQLXML 4.0)

THIS TOPIC APPLIES TO: yesSQL ServeryesAzure SQL DatabasenoAzure SQL Data Warehouse noParallel Data Warehouse

This Microsoft Visual Basic application uses ADO to establish a connection to an instance of Microsoft SQL Server and execute an updategram. The updategram updates the last name of a specific employee. This example uses the AdventureWorks sample database.

In this sample application:

  • The conn object (ADODB.Connection) establishes a connection to a running instance of SQL Server on a specific server computer.

  • The cmd object (ADODB.Command) executes on the established connection.

  • The command dialect is set to DBGUID_MSSQLXML.

  • The updategram is copied to the command stream (strmIn).

  • The command's output stream is set to the StrmOut object (ADODB.Stream) to receive any returned data.

  • Finally the command (updategram) is executed.

    Here is the sample code:

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=AdventureWorks; 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.Contact ContactID='64' Title='IsNULL'/>"  
    SQLxml = SQLxml & "    </updg:before>"  
    SQLxml = SQLxml & "    <updg:after>"  
    SQLxml = SQLxml & "       <Person.Contact ContactID='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  

Note

If you're using SQLXML from ADO to execute updategrams that specify an XSD schema, you must set the "SQLXML Version" property to "SQLXML.4.0" on the connection object, as shown in the following example line of code:

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

Specifying a Mapping Schema for the Updategram

This example illustrates how to specify and use a mapping schema in an updategram.

Save the following XSD schema (EmpSchema.xml) to your disk, and be sure to update the path that is specified in the code to the location of the mapping schema on your disk. The code assumes that the schema is saved on the C: drive in the Schemas folder.

<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.Contact" >  
   <xsd:complexType>  
        <xsd:attribute name="CID"    
                       sql:field="ContactID"   
                       type="xsd:string" />   
        <xsd:attribute name="MName"    
                       sql:field="MiddleName"    
                       type="xsd:string" />  
    </xsd:complexType>  
  </xsd:element>  
</xsd:schema>  

Because both XSD and XDR schemas can be specified, this is the equivalent XDR schema:

<?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.Contact" >  
       <AttributeType name="CID" />  
       <AttributeType name="MName" />  

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

This is the Visual Basic code to execute an updategram that has an associated mapping schema. The updategram updates the middle name for contact 1 in the Person.Contact table.

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=AdventureWorks; 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  

Passing Parameters

In the Visual Basic applications provided earlier, parameters are not passed. In this application, the ContactID and MiddleName values are passed as parameterized input to the 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 InputContactID As String  
  Dim InputMiddleName As String  

  InputContactID = "1"  
  InputMiddleName = "Q."  

  ' Open a connection to the instance of SQL Server.  
  conn.Provider = "SQLOLEDB"  
  conn.Open "server=(local); database=AdventureWorks; 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='ContactID'/>"  
  SQLxml = SQLxml & "<updg:param name='MiddleName' />"  
  SQLxml = SQLxml & "</updg:header>"  
  SQLxml = SQLxml & "<updg:sync >"  
  SQLxml = SQLxml & " <updg:before>"  
  SQLxml = SQLxml & "   <Person.Contact ContactID='$ContactID' />"  
  SQLxml = SQLxml & "</updg:before>"  
  SQLxml = SQLxml & "<updg:after>"  
  SQLxml = SQLxml & "<Person.Contact MiddleName='$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("@ContactID", adBSTR, adParamInput, 1, InputContactID)  
  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