Databases Reference
In-Depth Information
Webcrawler, or Hotbot, to name a few); where do you think the “hits”
come from?
If you're as much of an Internet junkie as I am, you may even go so far
as to check online to see what movies are playing in your local area. Two
online sites offer such information: http://www.movielink.com and
http://www.moviefinder.com. I enter my zip code, click the mouse a couple of
times, and I know what movies are playing at what theaters and their show
times. Why pick up the phone, call the theater, and get a recording that you
can barely hear? If you would rather stay at home and park yourself in front
of the couch with a bag of potato chips, try http://www.tvguide.com and you
can choose the television listings available by cable company. So, if you were
purchasing the Sunday paper just for the
magazine that came with
it, save yourself some money and cancel your subscription.
TV Week
These examples all have several things in common. The first is that the
Web browser is the client application. As a developer, you can now breathe
a sigh of relief knowing that you can completely concentrate your program-
ming efforts on the server-side interface to the data repository.
So how does it all work? Well, the short (and extremely simplified)
answer is that the client, you and your browser, initiate a process that
somehow interacts with the back-end database. This process is also
responsible for returning content back to the browser, although what it
returns may vary on what action was being performed. If you are merely
submitting personal information about yourself or making an entry into a
guest topic, the response might simply consist of a confirmation that the
information was successfully entered into the database.
As you can probably well imagine, there are a number of technologies
available today that would allow us to accomplish such tasks. We could opt
to adopt Common Gateway Interface (CGI) scripts, but this option is
replete with security risks, making it an unattractive solution to even expe-
rienced programmers. Active Server Pages (ASP), a Microsoft technology
designed to operate in conjunction with that company's Internet Informa-
tion Server (IIS) 4.0, is another possibility, but it locks us into an operating
system and a Web server that our Internet service provider (ISP) might not
be using. Of course, there are a number of other options available, but per-
haps one of the better but less explored ones is made possible by Java
servlets and JDBC™.
THE JAVA INCENTIVE
There are two key requirements for database programmers:
• They must have intimate knowledge of the language construct used to
manipulate databases.
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