Application Development

Application development is the most difficult and time-consuming of the three methods of interacting with a database. This approach is only considered when a computer program needs to access a database in order to query or update data that is relevant to the program.

For example, the software running on an ATM at a bank needs to access the bank’s central database to retrieve information about a customer’s account and then update that information while the transaction is being performed.

Applications that require databases can be written in virtually any programming language. For stand-alone applications, the most popular language for database programming is C++, with a growing following in the C# and Java communities. For web applications, Perl and PHP are the most popular languages, followed by ASP (and ASP.NET) and Python. Interest in using Ruby with the web and databases is growing, as well.

Many database access extensions for modern programming languages exist, and they all have their advantages and caveats. The expert database programmer will learn these caveats, however, and eventually become comfortable and quite skilled at manipulating database objects within application code.

Figure 4 and Figure 5 show the code for a simple database application written in Perl and its output, respectively.

With all the features of modern programming languages, extremely complex database applications can be written. This example merely glosses over the connection, query, and disconnection parts of a database application.