PHP and MySQL

PHP's is a widely-used programming language ideally suited for web development. If this is your first time using a programming language, you may want to find a book or online tutorial that speaks about programming in general. As a short summary, a programming language is a series of instructions that a computer first reads and then performs the actions you specify in the language. There are many languages for human speech, and the same applies with programming languages.

Specifically, PHP is a general purpose open-source scripting language. It uses a similar syntax to C++, Java, and Perl and looks vaguely like each of these languages. Although its most common application is for web-based programming, it can be used in a variety of other situations. As a scripting language, PHP code is parsed, or read, each time the code is loaded, meaning that there is no separate "compiler" that you must use before the code can be executed. When the code is used in a web page, it is inserted directly into the HTML, and, among other things, you can generate HTML dynamically. For details, visit PHP's official site.

PHP can operate as a stand-alone executable, but it is most commonly used as a web server component. The web server receives a request for a page, realizes that the page could contain PHP code, and routes it through the PHP parser. The parser executes the code and sends the output to the web server, which in turn sends the "parsed" file to the requester. Despite the apparent complexity, this all happens very quickly. The most important thing to realize is that because PHP is a server-based language, it is not dependent on web browsers or client configurations.

The "ASP", or active server pages, technology by Microsoft works in a similar fashion but it is designed to function exclusively under Microsoft's web server. As an open-source initiative, PHP has been adapted to work on many different web servers under most of the common operating systems currently used by web hosting companies. The most common and, arguably, the most secure and stable platform for PHP is under the Apache web server running on a Unix-like OS such as Linux or FreeBSD. This configuration is very popular: Apache is the most widely-used web server software on the Internet, and PHP is the most common Apache module. As of June 2003, PHP operated on over 12.3 million domains; at the same time, over 23 million domains, or 60%, operated the Apache web server.

The MySQL database is a production-level open-source database using the structured query language (SQL, commonly pronounced "c-quel"). MySQL often accompanies PHP on web hosting plans because they are both ideally suited for web development and they do not carry expensive licensing fees. Using PHP as the host language and MySQL as the database, you can create very powerful, full-featured web sites easily and quickly. For example, it takes only 4 lines of PHP code to connect to a MySQL database, query the database and output the results.

MySQL is possibly the best example of the potential for open-source software. In a recent side-by-side database test by eWeek Labs, a fully-optimized version of MySQL ran at virtually the same level as the world-renown (and very expensive) Oracle database, and it served content three times faster than Microsoft's SQL server.