Introduction

Being one of the most popular and approachable programming languages used on the web these days, PHP truly provides web developers with the tools for building a vast arsenal of applications which could not be created a few years ago. In truth, database-driven web sites, shopping carts, pagination systems and form validation mechanisms are only a few examples of what can be done with this friendly scripting language. PHP has evolved significantly and now exposes a mature object-oriented model.

However, it's valid to notice that aside from the wealth of web-based applications that can be built quite easily with PHP, there's one in particular that's becoming very popular with many modern web sites as they grow in size. In this case, I'm talking about developing an internal search engine for any web site, by using the capacities provided by the powerful MySQL/PHP 5 tandem.

True to form, web-based search engines have existed for a long time and evolved steadily, mostly due to the continuous advances of large companies like Yahoo, Google, and many others in this huge and fascinating terrain.

Nevertheless, in this case I'm not so ambitious as to tackle the development of such a complex project. Instead, I'd like to focus my attention on a concrete situation that several PHP developers have to face on a frequent basis. They must deal with a medium-sized web site that requires the implementation of an internal search engine, so users can find the contents they're looking for more directly and easily, without the need to navigate across a certain number of irrelevant web pages. Sounds pretty logical, right?

From a theoretical point of view, building this kind of application might seem to be a pretty straightforward process that can be tackled with minor hassles. But in a real-world situation, developing an efficient search engine with PHP 5 and MySQL may be quite challenging, especially if you're a PHP developer making your first steps into the vast area of web development.

Thus, considering that more and more web sites are adding a proprietary search engine to their existing structure, in this series, which is comprised of three instructive tutorials, I'm going to teach you how to build a web-based search application that can be easily adapted to suit your personal needs. Of course, as you may have guessed, I'm going to use some basic MySQL database tables for storing the contents of a hypothetical web site, but this condition can be quickly modified to work with a different database server.

Having introduced the subject of this series of articles, it's time to start learning how to develop an extensible search engine by using the powerful MySQL/PHP 5 combination. Let's begin this instructive journey now!