Learning PHP, MySQL & JavaScript, 4th Edition

Chapter 10. Accessing MySQL Using PHP

If you worked through the previous chapters, you’re proficient in using both MySQL and PHP. In this chapter, you will learn how to integrate the two by using PHP’s built-in functions to access MySQL.

Querying a MySQL Database with PHP

The reason for using PHP as an interface to MySQL is to format the results of SQL queries in a form visible in a web page. As long as you can log into your MySQL installation using your username and password, you can also do so from PHP.

However, instead of using MySQL’s command line to enter instructions and view output, you will create query strings that are passed to MySQL. When MySQL returns its response, it will come as a data structure that PHP can recognize instead of the formatted output you see when you work on the command line. Further PHP commands can retrieve the data and format it for the web page.

Note

In previous editions of the book, this chapter introduced the old mysql extension for accessing a MySQL database, before then moving onto discussing the newer mysqli extensions in the following chapter. But time marches on, as they say, and by now there should be very few legacy installations using the old code, so we’ll just go straight in and look at how to use this newer extension—which is pretty much standard everywhere nowadays.

The Process

The process of using MySQL with PHP is as follows:

1. Connect to MySQL and select the database to use.

2. Build a query string.

3. Perform the query.