How to connect php to mysql database?

I'm making a search engine for a website and I've never used PHP before and I have been trying to connect my webpage to a mysql database using this code: $dbhost = 'hosthere'; $dbuser = 'usernamehere'; $dbpass = 'passwordhere'; $conn = mysql_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('Could not connect: ' . mysql_error()); } echo 'Connected successfully'; but I also read not to use the mysql_* functions as they will soon not be usable any longer but I haven't seen that anywhere else. My old code to connect is: define('DB_SERVER', 'serverhere'); define('DB_SERVER_USERNAME', 'usernamehere'); define('DB_SERVER_PASSWORD', 'passwordhere'); define('DB_DATABASE', 'databasehere'); define('STORE_DB_TRANSACTIONS', 0); define('DEBUG', 0); db_connect() or die('Unable to connect to database server!'); Should I just stick with that or use the code at the top?