Once the database is up and running and populated with data, you will need a way of talking to it.
Command shells are pretty common and come bundled with just about every database.
These are usually simple filters which allow you to log on to the database, execute commands and receive output. They can either be very simple command-line shells or nice, fanciful graphical user interfaces. Whichever the case, command shells provide access to the database from the machine on which the database is running. We will see more examples of this methodology when we discuss CGI-based web databases in part three. Socket-based middleware does the exact same thing, but over a network.