To view live data in Design view, you must do the following:
When you enable Live Data, a temporary copy of the open document is sent to the folder for processing. The resulting page is returned and displayed in Design view, and the temporary copy on the server is deleted.
If the page displays an error message when you enable Live Data, make sure the URL prefix in the Site Definition dialog box is correct. For more information, see Connecting to a database.
If you have difficulty getting Live Data view to work, see Troubleshooting Live Data view.