Overview

An external link is used to link a workbook to other workbook or to external data. The most frequent occurrence for linking a workbook to other workbooks has to do with formulas. In this case, a formula references a range or name defined in another workbook. Hyperlinks on cells and other spreadsheet objects are also considered an external link. OLE links are yet another technology used to link the workbook to another object. Finally, Dynamic Data Exchange (DDE) servers can be used to access external data. DDE servers are accessed through formulas in the workbook.

The goal of the way in which external links are saved is to always write the target source in a relationship file, so that external resources are easily discoverable in lightweight relationship XML rather than deep in the application's XML.