The .WDB format is used by the Microsoft Works office suite to store database information and is similar to the .MDB used by Microsoft Access.
Microsoft Works is an office suite available from the Microsoft Corporation. It is considered by most to be a smaller, less expensive version of the Microsoft Office suite; it includes the Microsoft Works word processor, the Works spreadsheet, and the Works database.
Microsoft's Word is able to open (and save as) Works word processor documents, and Microsoft's Excel is able to open (and save as) Works spreadsheets.