Learning PHP 5 [Tapa blanda]

There are more new books being published about PHP than you can shake a joystick at. PHP (along with program friends - MySQL and Apache) has become very popular among developers and web designers, and for good reason. As a programming language, it is particularly suited to web development projects, while being relatively easy to write, use and learn. More importantly, it's open-source and free, cross-platform, and widely supported.

The book, "Learning PHP5", by David Sklar, is one of the latest volumes dealing with PHP. It describes itself as "a Pain-Free Introduction to Building Interactive Web Sites" and provides a gentle introduction to the latest version of PHP, which is version 5 and only recently available.

This book is not particularly useful for those experienced already with PHP, nor for those wanting to upgrade their knowledge of PHP from versions 4 and earlier to the newest version. It probably is not particularly useful for those power programmers who need and want a deep and comprehensive coverage of the topic. But it is a very well-written and designed introduction to PHP 5 for beginning programmers or those experienced PERL, ASP, or Cold Fusion programmers who want to learn a different language. There are many illustrations and code samples sprinkled throughout the book. Sklar, however, occasionally skims over some topics in furtherance of the completion of some practical examples.

The publisher is O'Reilly Media, Inc. which seems to have an editor's policy of covering complex computer-related topics in a comprehensive manner by publishing a range of volumes covering different aspects of a topic or from different angles or for different audiences. O'Reilly also publishes volumes on moving to PHP 5 ("Upgrading to PHP 5"), detailed and technical PHP ("Programming PHP"), and a collection of solutions to common PHP programming problems ("The PHP Cookbook").

The author, Mr. Sklar, is an experienced consultant in computer software development and technical training. He is the author of "Essential PHP Tools" and coauthor of the afore-mentioned "The PHP Cookbook". He takes a deliberate and comprehensive approach to explaining PHP 5, not in great depth, but with an intent of providing enough information, concepts, detail, and scope to create a pleasant and useful read of a technical subject. The basic promise of PHP is in the relatively easy creation of more dynamic and

interesting web sites which would include, for example, product catalogs, blogs, photo galleries, event calendars, forms, and more.

There are 13 chapters and 3 appendices. The early chapters provide an orientation to PHP including its place in contemporary web development, its basic rules, and its syntax. They explain the basic background of PHP and how it interacts with the browser and web server. Later chapters introduce primary concepts like loops, arrays, and functions. The idea here is to facilitate learning the fundamentals of the grammar and vocabulary. Chapters 2 through 12 have short exercises at the end of each to allow the reader to practice writing PHP code and to test learning. (The answers are contained in Appendix C.) Experienced programmers and geeks may recoil at the inclusion of these exercises, but they are useful for beginners.

Chapter 6 provides a practical exercise - how to make and use a web form. The author shows how to access form variables, how to validate user-inputted data for security and efficiency reasons, and how to process forms using functions. Chapter 7 shows how PHP interacts with database programs, like SQL and Oracle, but focuses primarily on MySQL, and demonstrates how to organize data, connect to a server-based database, create tables, and input and retrieve data.

The rest of the middle chapters cover the use and implementation of cookies and sessions, handling dates and time, and working with files. The practical exercise using dates and times is creating and displaying a monthly calendar. The final chapters provide brief but practical coverage of XML, debugging, and in Chapter 13, other PHP aspects. PHP is amazingly useful, flexible, and practical. One can deal with graphics, pdf-formatted documents, and other media like Flash and Shockwave. It also has mailing and file uploading functions, encryption capabilities, and for more experienced coders, the ability to run shell commands. The upgraded PHP 5 has new capabilities which now include object-oriented programming.

Appendix A covers installing and configuring PHP for Windows, Mac OSX, and Linux; Appendix B is a short primer on regular expressions and how to use them with PHP.

I found the book to be the most accessible introduction to PHP I have read. It provides the basic fundamentals, engages the reader in practical examples, reinforces learning with exercises, and provides an overall perspective on the scope of PHP programming.

Code examples used in the book can be downloaded at the O'Reilly site. More information is available at www.oreilly.com/catalog/learnphp5/index.html.

From the title I would have expected that the book spend all of it's slim 300 page frame on a soup to nuts language introduction. For the first six chapters it looks that way as it rolls through language basics, variables, conditionals, arrays, etc. But then it veers into the practical for the rest of the book and covers topics such as database access through Pear DB and the use of XML.

There is a lot to like about this book. The chapters are short, focused and practical. And I have no issues recommending the book on a technical level. Especially the database section which advocates simple safe SQL practices. In particular you should follow the advice on page 126 about using the '?' operator in your SQL queries.

There isn't much new for PHP 4 programmers looking to learn about PHP 5. In fact there is little or no emphasis placed on teaching you to write classes. The only information about classes is about their consumption. This is definitely not a book for the experienced PHP developer, but for a beginner this is one of the best.

I picked up this book shortly after PHP 5 became available, expecting that because it's specifically about PHP 5 it would give some attention to PHP 5's new features over PHP 4. Most specifically I wanted to read about PHP 5's completely new Object Model, which is not a minor change. This book only mentions objects and classes in passing though, so it wasn't helpful to me at all in that regard. The chapter on working with databases has been helpful to me. It focuses mainly on PEAR DB but includes some good information about PHP 5's improved MySQL functions.

It's still a helpful book for programming PHP in general, and I do check it from time to time to brush up on syntax or look at example code. It reads pretty well and the examples are solid. If you're coming to PHP with prior experience in Java, Perl, or anything similar, you'll probably find the pace pretty slow. If you want a well-rounded introduction to PHP you'll do well with this book. If you're looking for information on more advanced topics like object-oriented programming, look elsewhere.