The database menu is used for saving and loading the rack data. The "save" and "load" options are self-explanatory, and they can be accessed with control-s and control-l from the database window.
The file format for saving and loading is a plain text file with SQL queries that will first make all the tables from the database, and then insert the rows. If necessary, you can modify these files with a text editor to make changes to the data or the database structure.