where do i put the name of my database

Hi all please need your help on the code below.
where do i put the name of my database.
I see where to put the user name and pw but i am not sure of where to put the name of the database,. thanks



<?php
$db = mysql_connect("localhost", "username", "password") or die("Could not connect.");
if(!$db)
die("no db");
if(!mysql_select_db("database_password",$db))
die("No database selected.");

 

Replace database_password with the database name
if(!mysql_select_db("database_password",$db)) die("No database selected.");

 

Thanks
it worked now
I appreciate