Reusable Code

You've just seen the most simplistic way to connect to MySQL. It's often more

useful, however, to “package” the above code in a function or a class so it can be

reused.

As a function we could have:

File: 2.php

<?php

function &connectToDb($host, $dbUser, $dbPass, $dbName)

{

// Make connection to MySQL server

if (!$dbConn = @mysql_connect($host, $dbUser, $dbPass)) {

return false;

}

// Select the database

if (!@mysql_select_db($dbName)) {

return false;

}

return $dbConn;

}

$host = 'localhost'; // Hostname of MySQL server

$dbUser = 'harryf'; // Username for MySQL

$dbPass = 'secret'; // Password for user

$dbName = 'sitepoint'; // Database name

$dbConn = &connectToDb($host, $dbUser, $dbPass, $dbName);

This reduces the process of connecting to MySQL and selecting a database to a

single line (two if you count the include statement, which would point to a

separate file containing the connectToDb function):

$dbConn = &connectToDb($host, $dbUser, $dbPass, $dbName);

Note that we've used the reference operator &. This operator and the role it plays