In this lesson we will create a new MySQL database using phpMyAdmin and a config.php file in the site root with connection's parameters for the database (database name, database host, username, password).
Open config.php and copy and paste the code replacing the value of variables $db_host, $db_name, $username, $password, with correct parameters.
<?php
// Connection's Parameters
$db_host="localhost";
$db_name="database_name";
$username="database_username";
$password="database_password";
$db_con=mysql_connect($db_host,$username,$password);
$connection_string=mysql_select_db($db_name);
// Connection
mysql_connect($db_host,$username,$password);
mysql_select_db($db_name);
?>
// Connection's Parameters
$db_host="localhost";
$db_name="database_name";
$username="database_username";
$password="database_password";
$db_con=mysql_connect($db_host,$username,$password);
$connection_string=mysql_select_db($db_name);
// Connection
mysql_connect($db_host,$username,$password);
mysql_select_db($db_name);
?>
Now, in the site root, create index.php file and use PHP include() function to include config.php into the page.
<?php include('config.php') ?>
This is a simple way to enstablish a connection with your database MySQL to be used when you need to execute a SQL query.
The index.php structure will be explained in the next lessons.
I am 
Thanks for this post!
very helpful
Can this use php mail() function?
Why do you connect and select the database twice? The first time is enough :)
I suggest include_once("config.php"); be used for the includes, as it includes the configurations only once.