One of my favourite things about PHP 5 is how nifty the object-oriented features are. I have been able to put together surprisingly robust web applications using simple class hierarchies and abstract classes, features that only took off in PHP with the version 5.0 release. One of the other things I have loved is using the the various built-in object-oriented classes provided by the runtime, most notably the mysqli and related functionality.

One extremely common task I complete is to use database storage for session data. When you are running multiple web servers and individual HTTP requests might go to different machines, trying to come up with a scheme to synchronise session data files between the individual servers becomes prohibitive. Far better a solution is to simply put these data in the database server along with everything else (see Figure 1) – your application servers hold only the code needed to generate the pages from the database.

As I sat down to edit “Core Web Application Programming with PHP and MySQL”, I would sometimes find errors in the text so blindingly obvious and stupid that I would question whether or not I was truly qualified to write such a book. And yet, after talking with some other people who write books (and recalling days when I wrote huge amounts of code), it seems that this is all common and with much proof-reading and the hard work of some friendly reviewers, I was able to write a book of extremely high quality.

Of course, that just meant I would be even more devastated when the first technical errors WERE found in the book.

There have been a couple, but they’re not that killer serious.