In this section, we will look at the overall
architecture and deployment context of web based applications and see how this
leads to their peculiar management challenges. Unlike conventional applications
that can be monolithic, web applications are by their very nature amenable to
layering. One cannot have a monolithic web application as the client and the
rest of the application have to be of necessity separated. In principle, one
could have a thick client application with a lot of intelligence embedded at
the client end, but that would defeat the very purpose of delivering an
application over the web. The idea is to have a client that is common to all
users so that anybody can access the application without having to do anything
special. This client is typically a browser of some sort that can render a HTML
page on the user’s screen.
Most of the processing is done at the other end of
the application, that is, at the server. Here again there can be separation
between the application and the data storage in the database. These two layers
can be on separate machines that are themselves separated over the network.
The layering approach can bring about much greater
flexibility and simplicity in design, maintenance and usage. In a monolithic
application, everything is coupled together and in a layered application, we
can change one layer without affecting the behavior of others. For example,
the business logic at the application layer can be changed without affecting
the user interface or the database design. We can change the database
management system from one vendor’s offering to another without changing the
application code or the user interface.
- · Those with static text
- · Content that is changed frequently
- · Interactive websites that act on user input
- · Portals that are merely gateways to different kinds of websites
- · Commercial sites that allow transactions
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