Databases Reference
In-Depth Information
Figure 11-1
Connect to server dialog box.
A
connection,
in the simplest terms, is a communication path. Whenever
you use the telephone you establish a connection, a communication path
between you and another person that enables you to talk. You also establish a
connection when you use your browser to visit a Web site, or when you talk to
someone through
instant messaging (IM),
which is a type of communication
application enabling conversations between users over the Internet. The same is
true when you connect to a database server; you establish a communication path
between the client and the server.
In the classic client/server model, like the one shown in Figure 11-2, end-
user PCs are the clients connecting to a database server. The server contains the
application programs, the DBMS, and the database, which all of the clients share.
When an end user wants to run an application or retrieve data from the shared
database, the client computers handle the initial processing of the request. The
request is sent on to the server for processing by the application code, includ-
ing data retrieval from the shared database, as necessary. The server returns the
results to the client PC where the client is responsible for formatting the screen
display.
