With almost any application written for the Web nowadays, a highly interactive application is of limited value if the interaction between its users isn't permanently saved. You have to integrate your application with a proper database to solve this issue. Imagine a case where all of the data for your application (registered users, order transactions, and social interactions) was stored within the temporary memory of the server the application is running on. The moment that server is turned off or rebooted, all of your application data will be lost. Relying on a database to store this data permanently is crucial to any dynamic application.
In this chapter, the following topics will be covered: