A Microsoft Data Link file or Universal Data Link is a universal file that links to a specific database and can be used by many different applications.

The way a .UDL file is initially created depends on your Windows installation. This can be created  desktop shortcut menu.

1. Right-click on the Desktop, or in the folder where you want to create the file.
2. Select “New” from the shortcut menu. If Microsoft Data Link is listed, select it.
3. Windows 2000 will most likely not have a Microsoft Data Link listed. If this is the case, please refer to the next section.

If no Microsoft Data Link is listed, the following steps should fix this.

1. Right-click on the desktop, or in the folder where you want to create the file.
2. Select New, then Text Document.
3. Give the Text Document any name with a .UDL extension (“Show file extensions” must be enabled in folder options).
4. A window will pop up warning that “If you change a filename extension, the file may become unusable. Are you sure you want to change it?” – select Yes.
5. You have now successfully created a .UDL file.

At this point you have a Microsoft Data Link file. In order to use this in a database application, a couple more tasks need to be accomplished. In this case, you need to link the .UDL file to an Access database.

1. Open Access. Select Blank Access Database and click OK.
2. In the File New Database window, save the Database in a location of your choice with any .MDB or .ACCDB extension name.
3. At this point you can close Access (just remember where you saved the database to).
4. Go back to the .UDL file that was created previously and double-click on it (this is where a link to the Access database is created).
5. Click the Provider tab. For .MDB files, select “Microsoft Jet 4.0 OLE DB Provider”. For .ACCDB files, select “Microsoft Office 12.0 Access Database Engine OLE DB Provider”.
6. Click the Connection tab. Navigate to the .MDB or .ACCDB Access Database that was created in step 2. Now, the .UDL file is ready to be used in LabVIEW.

There are a couple of different methods to communicate with Access in LabVIEW, and some are more difficult than others. You can use ActiveX Automation to open Microsoft Access and control many aspects of the Access Application. For actual database manipulation however, the Access automation classes rely upon the Microsoft DAO (Data Access Object) and/or ADO (ActiveX Data Object) classes. These classes can be used independently or through the Access automation classes to read and write data into an Access database. These classes can be difficult to use and may require a fair amount of SQL knowledge to accomplish a complicated task.

For more information about the Microsoft Access automation classes, DAO or ADO classes refer to the Microsoft website and Developer Network.It is also possible to use Dynamic Data Exchange (DDE) communication between LabVIEW and Access. DDE is a Microsoft technology that preceded COM and ActiveX. DDE is NOT recommended as it is considered by most to be obsolete. However, examples still ship with LabVIEW that demonstrate how to communicate with MS Access using DDE. The examples are located in ..\LabVIEW\examples\comm\access.llb

Note: The LabVIEW Database Connectivity Toolset is the preferred method of database communication with LabVIEW. The LabVIEW Database Connectivity Toolset offers many powerful tools and extended capabilites for quickly accessing databases. The LabVIEW Database Connectivity Toolset offers connectivity to most popular databases through Microsoft ADO technology, complete SQL Functionality, and the ability to save records in XML format. It provides both easy-to-use and advanced functions to allow common database operations as well as detailed database accessibility. The LabVIEW Database Connectivity Toolset is sold separately or in the LabVIEW Enterprise Connectivity Toolset along with the LabVIEW Statistical Process Toolkit and the LabVIEW Internet Developers Toolkit.