Connection in PHP we use this code:

<?php //Start PHP statement
 $link = mysql_connect('localhost', 'mysql_user', 'mysql_password'); //this is the MySql connection function with passing parameter

 if (!$link) {
  die('Could not connect: ' . mysql_error()); //this is show the connection error
 }
 echo 'Connected successfully'; //It show the message connection successfully or not
 mysql_close($link); //connection close here
 ?> //End PHP statement