Using ICommandStream to Set an XML Command
The OLE DB (version 2.6) interface ICommandStream passes a command as a stream object rather than as a string.
This interface allows command to be in any encoding that the XML parser understands. When ICommand::Execute is called, the command text is read out of the stream directly and no conversion is required. Therefore, executing XML commands using ICommandStream interface is more efficient.
To set XML as a command using ICommandStream and retrieving the result as an XML document