Data in an Excel workbook can come from two different locations. The data may be stored directly in the workbook, or it may be stored in an external data source, such as a text file, a database, or an Online Analytical Processing (OLAP) cube. The external data source is connected to the workbook through a data connection, which is a set of information that describes how to locate, log in, query, and access the external data source.

When you are connected to an external data source, you can also perform a refresh operation to retrieve the updated data. Each time that you refresh data, you see the most recent version of the data, including any changes that were made to the data since it was last refreshed. Connection information can either be stored in the workbook or in a connection file, such as an Office Data Connection (ODC) file (.odc) or a Universal Data Connection (UDC) file (.udcx).

Microelectronics Jacob Milliman Grabel. Connection files are particularly useful for sharing connections on a consistent basis and for facilitating data source administration. Euro Truck Simulator 2 Mods Maps Europe Google. If you use a connection file to connect to a data source, Excel copies the connection information from the connection file into the Excel workbook. When you make changes by using the Connection Properties dialog box, you are editing the data connection information that is stored in the current Excel workbook, and not the original data connection file that may have been used to create the connection, indicated by the file name that is displayed in the Connection File property.