Quite a while ago now I posted a blog about how to interact with a database to save the star ratings from my Star Rating Script built with YUI. I recommend you do not follow the guidelines in that post any more because it uses an old method of database interaction with PHPs built-in
mysql_* functions, which are really not secure any more and deprecated in the newest version of PHP.
What you should be using for database interactions from PHP these days is what is known as PDO, which stands for PHP Data Objects. From the PHP website:
The PHP Data Objects (database-specific PDO driver to access a database server.
PDO provides a data-access abstraction layer, which means that, regardless of which database you're using, you use the same functions to issue queries and fetch data. PDO does not provide a database abstraction; it doesn't rewrite SQL or emulate missing features. You should use a full-blown abstraction layer if you need that facility.