You’ve come to a watershed moment in your programming career, however brief you feel that career has been. Up until this point in the book, you’ve been using a lot of PHP constructs—from
if statements to some basic functions to constants and even error handling. You’ve also become familiar with the basic MySQL interactions you’ll need in most PHP scripts. With what you already know, you’re ready to take on most of the basic programming problems you’ll run across in a typical web application—as long as you’re thinking on a single-page level.
In other words, if you have a form that gathers information, you can handle that. You can grab information from a table, and you can put information into a table. You can respond to errors, redirect users, and even distinguish between a good user experience and a bad one.
In spite of all that, you know that web applications are greater than the sum of their single-page interactions. Ten different pages that interact with ten different tables is a much simpler situation than a complete web application that has ten pages, particularly when those ten tables connect and interact with one another, and even relate information in one table to information in another. Add to that image handling (something you started to dig into in order to finish your user form), some interaction with Facebook and Twitter, and allowing users to actually log in, and things get a lot trickier.
And that’s what’s next: the jump from ...