FIGURE 28.6 The user starts a GUI database program on the user’s
workstation (hostname Cheetah). This program, which is the database
client, then connects to the database server running on the host Simba.
Web Access to a Database
This section looks at two basic examples of web access to the database server.
In the first example, a user accesses the database through a form located on
the World Wide Web. At first glance, it might appear that the client is running
on the user’s workstation. Of course, in reality it is not; the client is actually
running on the web server. The web browser on the user’s workstation simply
provides a way for each user to enter the data that the user wants to send to
the database and a way for the results sent from the database to be displayed
to the user. The software that actually handles sending the request to the
database is running on the web server in the form of a CGI script; a Java
servlet; or embedded scripting such as the PHP or Sun Microsystems, Inc.’s
JavaServer Pages (JSP).
Often, the terms client and front end are used interchangeably when speaking
of database structures. However, Figure 28.7 shows an example of a form of
access in which the client and the front end are not the same thing at all. In
this example, the front end is the form displayed in the user’s web browser. In
such cases, the client is referred to as middleware.
FIGURE 28.7 The user accesses the database through the World Wide Web.