Important Notice for PHP DevCenter Readers About O'Reilly RSS and Atom Feeds  O'Reilly Media, Inc. is rolling out a new syndication mechanism that provides greater control over the content we publish online. Here's information to help you update your existing RSS and Atom feeds to O'Reilly content.  [PHP DevCenter]

Calculating Entropy for Data Miners  Quick--what's the relationship between the columns of your database? Don't know? Maybe it's time to pull out the information theory book and calculate how much data they store. Paul Meagher explains how this works while showing off premade PHP libraries to handle the details of the calculations for you.   [ONLamp.com]

Programming eBay Web Services with PHP 5 and Services_Ebay  PHP 5 added several new features to the language, yet laundry lists and high-level overviews don't really show what they are or why you might use them. Fortunately, Adam Trachtenberg writes for us. Here's how to use the new features of PHP 5 for writing web services clients.   [ONLamp.com]

Calculating Entropy for Data Mining  Eww, statistics. Right? Not necessarily--for example, calculating the entropy of your web statistics can help you analyze trends and correlations. Paul Meagher demonstrates statistical programming in PHP while explaining single-variable entropy.   [ONLamp.com]

Three-Tier Development with PHP 5  Well-factored applications separate data storage, manipulation, and display. For PHP programmers, PHP 5 and PEAR make that easier than ever. Luis Yordano Cruz demonstrates how to combine PEAR::DB_DataObject, Smarty, and PHP 5 to improve the design and maintenance of your applications.   [ONLamp.com]

Writing "Learning PHP 5"  Developers often write open source software in public, but what about developers who write about open source software? Do they build tools? How do your favorite books come about? David Sklar explains how he wrote Learning PHP 5.   [ONLamp.com]

Allowing Registration-Required Binary Downloads  You have a great PDF, MP3, or binary file to distribute, but you want to know who's downloading it. How hard could it be to write a little PHP program to require registration before letting your goodies loose? Robert Bernier demonstrates that it's actually pretty easy.   [ONLamp.com]

Migrating to Page Controllers  Simple web apps can start simple, but when they grow more complex, they often need pruning and refactoring to be maintainable. The Page Controller design pattern can help separate concerns such as templates and logic. Ethan McCallum demonstrates this language-neutral technique with PHP.   [ONLamp.com]

PHP Form Handling  If your PHP program is a dynamic web page (and it probably is) and your PHP program is dealing with user input (and it probably is), then you need to work with HTML forms. David Sklar, author of Learning PHP 5, offers tips for simplifying, securing, and organizing your form-handling PHP code.   [ONLamp.com]

Simplify Business Logic with PHP DataObjects  Are you sick of writing the same SQL over and over in your application? Would you like to simplify and unify your access to the same tables in multiple places? DataObjects may be for you. Darryl Patterson demonstrates how to write and use DataObjects in PHP.   [PHP DevCenter]

PHP Debugging Basics  Whether you're a PHP newbie or a wizard, your programs are going to have bugs in them. Nobody's perfect. David Sklar, author of Learning PHP 5, provides techniques for finding and fixing the problems in your programs.   [ONLamp.com]

ANOVA Statistical Programming with PHP  Data miners and researchers often have to review their work for statistical variances. The Analysis of Variance technique is a popular and effective way to gauge the effects of an experiment. Paul Meagher demonstrates how to use PHP, MySQL, and JpGraph for productive data-mining work.   [PHP DevCenter]

Getting Started with PHP's HTML_QuickForm  Web programming can be dull the second time you have to validate client parameters or render data to form elements. Fortunately, PHP's HTML_QuickForm class simplifies the creation, processing, and validation of client parameters. Keith Edmunds explains how to start using QuickForm.   [PHP DevCenter]

Why PHP 5 Rocks!  Adam Trachtenberg provides a quick tour around PHP 5, highlighting seven of his favorite new features. These features (including better support for OOP, bundled SQLite, iterators, and more cool stuff) will allow your PHP 5 code to be more concise, more elegant, and more flexible than ever. Adam is the author of the upcoming Upgrading to PHP 5.   [ONLamp.com]

Building a PHP Front Controller  It's a rare web app that doesn't span multiple pages. It's also rare that such an app doesn't have some common behavior. The Front Controller design pattern can simplify processing, behavior, and the user experience. Ethan McCallum explains how to use this in your applications.   [ONLamp.com]

Using Shared Memory from PHP  At some point, you'll need to communicate with another process. Unix systems support a powerful IPC mechanism called shared memory that you can use to share information between processes. Alexander Prohorenko explains the basic theory and demonstrates how to use it from PHP.   [PHP DevCenter]

User-Friendly Form Validation with PHP and CSS  Any non-trivial web application processes form data, and every secure web application has to validate that data on the server. Balancing security with user-friendliness can be tricky. Jeff Cogswell demonstrates one approach.   [PHP DevCenter]

Features
Creating and Consuming Web Services With PHP  Find out how to create XML-RPC, SOAP and REST web services using PHP, the most popular scripting language for web applications.   [webservices.xml.com]

PHP Foundations
Using MySQL from PHP, Part 2  One of PHP's prime benefits is its close integration with databases, especially MySQL. Having explained the basics of MySQL, John Coggeshall turns his attention to demonstrating how to use MySQL from PHP. This week, learn how to count results, handle errors, and handle picky details.   [PHP DevCenter]

Database Templates with MySQL  After designing a few databases for clients, you'll likely start to see design similarities. Why not exploit those patterns to create templates for further customization? Russell Dyer demonstrates how to create and customize generic MySQL table templates.   [ONLamp.com]

PHP Foundations
Using MySQL from PHP  One of PHP's prime benefits is its close integration with databases, especially MySQL. Having explained the basics of MySQL, John Coggeshall turns his attention to demonstrating how to use MySQL from PHP.   [PHP DevCenter]

Web App Security Testing with a Custom Proxy Server  Assuming users will only access your web applications as you intend may be the best way to invite abuse. Attackers have tools to build bogus responses, so why not use the same techniques to toughen your own sites? Nitesh Dhanjani demonstrates how a custom proxy server can help you test the security of your web apps.   [PHP DevCenter]