Writing the programs

Your programs perform the tasks for your Web database application. They create the display that the user sees in the browser window. They make your application interactive by accepting and processing information typed in the browser window by the user. They store information in the database and get information out of the database. The database is useless unless you can move data in and out of it.

The plan that you develop outlines the programs that you need to write. In general, each task in your plan calls for a program. If your plan says that your application will display a form, you need a program that displays a form. If your plan says that your application will store the data from a form, you need a program that gets the data from the form and puts it in the database.

The PHP language was developed specifically to write interactive Web applications. It has the built-in functionality needed to make writing application programs as painless as possible. Methods were included in the language specifically to access data from forms, to put data into a MySQL database, and to get data from a MySQL database.