[JPU]

First, you will need to make a PHP script with this code
Please modify it to fit your settings

<?php
 #Modify this with your info
 $sql_localhost='localhost';
 $sql_user_name='root';
 $sql_user_pass='';
 $sql_data_base='test_db';
 #Do not edit this unless you know what you are doing#
 $sql_c=mysql_connect($sql_localhost,$sql_user_name,$sql_user_pass);
 if(!$sql_c) die('Could not Connect:'.$mysql_error());
 $sql_seldb=mysql_select_db($sql_data_base);
 if(!sql_seldb=mysql_select_db) die('Could not connect to database:'.mysql_error());
?>

Name that file above anything you want (EXAMPLE : connect.php)

Now you can simply connect to your database in any php script by just having this code on the php script

include('connect.php');

NOTE : If you have a file which you create a function, make sure you put this inside the function (EXAMPLE)

<?php
 include('connect.php');
 function echorandom(){
  include('connect.php');
 }
?>