Working with the XML Data Type in Applications

This topic describes the options that are available to you for working with the xml data type in your application. The topic includes information about the following:

  • Handling XML from an xml type column by using ADO and SQL Server Native Client

  • Handling XML from an xml type column by using ADO.NET

  • Handling xml type in parameters by using ADO.NET

Handling XML from an xml Type Column by Using ADO and SQL Server Native Client

To use MDAC components to access the types and features that were introduced in SQL Server 2005, you must set the DataTypeCompatibility initialization property in the ADO connection string.

For example, the following Visual Basic Scripting Edition (VBScript) sample shows the results of querying an xml data type column, Demographics, in the Sales.Store table of the AdventureWorks2008R2 sample database. Specifically, the query looks for the instance value of this column for the row where the CustomerID is equal to 3.

Const DS = "MyServer"
Const DB = "AdventureWorks2008R2"

Set objConn = CreateObject("ADODB.Connection")
Set objRs = CreateObject("ADODB.Recordset")

CommandText = "SELECT Demographics" & _
              " FROM Sales.Store" & _
              " INNER JOIN Sales.Customer" & _
              " ON Sales.Store.BusinessEntityID = sales.customer.StoreID" & _
              " WHERE Sales.Customer.CustomerID = 3" & _
              " OR Sales.Customer.CustomerID = 4"
ConnectionString = "Provider=SQLNCLI10" & _
                   ";Data Source=" & DS & _
                   ";Initial Catalog=" & DB & _
                   ";Integrated Security=SSPI;" & _

'Connect to the data source.
objConn.Open ConnectionString

'Execute command through the connection and display
Set objRs = objConn.Execute(CommandText)

Dim rowcount
rowcount = 0
Do While Not objRs.EOF
   rowcount = rowcount + 1
   MsgBox "Row " & rowcount & _
           vbCrLf & vbCrLf & objRs(0)

'Clean up.
Set objRs = Nothing
Set objConn = Nothing

This example shows how to set the data type compatibility property. By default, this is set to 0 when you are using SQL Server Native Client. After you set the value to 80, the SQL Server Native Client provider will make xml and user-defined type columns appear as SQL Server 2000 data types. This would be DBTYPE_WSTR and DBTYPE_BYTES, respectively.

SQL Server Native Client must also be installed on the client computer and the connection string must specify it for use as the data provider with "Provider=SQLNCLI10;...".

To test this example

  1. Verify that the SQL Server Native Client is installed and that MDAC 2.6.0or later is available on the client computer.

    For more information, see SQL Server 2008 R2 Native Client Programming.

  2. Verify that the AdventureWorks2008R2 sample database in SQL Server is installed.

    This example requires the AdventureWorks2008R2 sample database. For more information, see Considerations for Installing SQL Server Samples and Sample Databases.

  3. Copy the code shown previously in this topic and paste the code into your text or code editor. Save the file as HandlingXmlDataType.vbs.

  4. Modify the script as required for your SQL Server installation and save your changes.

    For example, where MyServer is specified, you should replace it with either (local) or the actual name of the server on which SQL Server is installed.

  5. Run HandlingXmlDataType.vbs and execute the script.

The results should be similar to the following sample output:

Row 1

<StoreSurvey xmlns="">
  <BankName>Primary International</BankName>

Row 2

<StoreSurvey xmlns="">
  <BankName>United Security</BankName>

Handling XML from an xml Type Column by Using ADO.NET

To handle XML from an xml data type column by using ADO.NET and the Microsoft .NET Framework you can use the standard behavior of the SqlCommand class. For example, an xml data type column and its values can be retrieved in the same way any SQL column is retrieved by using a SqlDataReader.However, if you want to work with the contents of an xml data type column as XML, you will first have to assign the contents to an XmlReader type.

For more information and example code, see "XML Column Values in a Data Reader" in the Microsoft .NET Framework 2.0 SDK documentation.

Handling an xml Type Column in Parameters by Using ADO.NET

To handle an xml data type passed as a parameter in ADO.NET and the .NET Framework, you can supply the value as an instance of the SqlXml data type. No special handling is involved, because xml data type columns in SQL Server can accept parameter values in the same way as other columns and data types, such as string or integer.

For more information and example code, see "XML Values as Command Parameters" in the Microsoft .NET Framework 2.0 SDK documentation.

See Also