• Part 1 - This is a hands-on video where I hope the viewer will actually write code along with me. I want to stress that this video (like everything else on this site,) targets beginners .. not old PHP hacks.
• Part 2 - In this video, we actually use the object we created in Part 1, in our PHP page.
• Part 3 - In this video, I clarify a point I was trying to make in part 2. In a nutshell, I talk about why it makes sense to keep any page rendering code (HTML and CSS) out of your business logic classes.

Lots of other videos (on different topics too) are also posted on Stefan's website.

In part three, they focus more on the last type of "block" in their list - the constant:

Some real-world constants, such as pi, the speed of light, the number of inches in a foot, and the value of midnight, are values that don't change. PHP not only provides its own predefined constants but lets you create your own. Using constants makes it easy to write and maintain your programs.

There's talk of the define() and constant() functions and a mention of some of the predefined and "magic constants" as well.

They go through each, explaining what they are, how they're used and when you'd want to use them in your code. They explain the data types and how those fit with each "container" and some basic things like valid names and how to assign things correctly.

They even get get into working with variables from GET and POST requests as well as working with the scope of variables and getting the metadata about them (is it an integer? is it empty?)

There's compile and install directives for each of the pieces of software, and even a question about libxml there at the end for those having installation issues with it.

Welcome to part 3 of the "Building an advertising system with PHP" series. In the previous parts (part 1 and part 2) I have shown you how to build your own advertising system using PHP and JavaScript. We've also added two extra features to our ad system and in part 2 we built a page to manage the ads as well. If you haven't read either part yet, I highly recommend doing so before reading this part.

In this part, the final part of the series, I will show you how to first track all kinds of statistics on each ad, and after that display neat graphs using PHP/SWF Charts. Let's get started.

Now that the front even of the system is all set up, they help you create the backend - gathering data, analyzing the traffic, and creating the graphs to map out the results. It'll require