preventing direct access to a php page, only access if redirected

Question

I want to make my php page only accessible from another page redirect and prevent my user from accessing it directly.

I mean, let\'s say I have a page called

Answer 1

To prevent access to pages, the best practice is to use session variables say $_SESSION['username'] and $_SESSION['password'] to check against your database table record assuming your table name is "users", the fields 'username' and 'password' in order for users to gain access to the page, else they are redirected to the log in page for them to supply the correct username and password through the input field.

Below is an anatomy of Preventing Direct Access to a PHP Page.

session_start();

$username=$_POST['username'];
$password=$_POST['password'];

$query="select * from users where username='$_SESSION[username]' and     password='$_SESSION[password]'";

$result=mysql_query($query);

if($result)
{

echo "Your login was successful..";// the page you want to go to if login successful
{
else
{

header("Location:index.php?action=login");//any page you want to return to if log in failed
}