Client/server describes the relationship between two computer programs in which
one program, the client, makes a service request from another program, the server, which
fulfils the request.
Although programs within a single computer can use the client/server
idea, it is a more important idea in a network. In a network, the client/server model
provides a convenient way to interconnect programs that are distributed efficiently across
different locations. Computer transactions using the client/server model are very
For example, to check your bank account from your computer, a client program
in your computer forwards your request to a server program at the bank. That program
might in turn forward the request to its own client program that sends a request to a
database server at another bank computer to retrieve your account balance. The balance is
returned back to the bank data client, which in turn serves it back to the client in your
personal computer, which displays the information for you.