Dynamic data exchange (DDE) is a protocol for Microsoft Windows that enables two applications to "talk" to each other—to exchange data continually and, if you want, automatically. Because DDE automates the manual cutting and pasting of data between applications, it provides a vehicle for updating data.
For example, you may want to use a communications program to periodically download data and store it in your database. Or you may want to supply the results of a query to a document in Microsoft Word. Using DDE, you can perform these kinds of inter-application operations automatically.