Sorry for the delay in responding. I've had my head up the rear end of a installation problem. I was just looking for my post on it to close the query.
BobbyS wrote:So even if I have an addon domain I can run a website on my main domain and the addon domain with one database?
Yes, I believe so, though have not attempted such.
My php skills are trully dreadful, so best if others provide details or you have a look at
http://uk3.php.net/manual/en/ref.msql.php. There's a nice bit of example code a couple of scrolls down on that page.
There are many issues to consider, not least making the web vs data relationship making plain sense.
Note that it's the php code that makes the connection and then interacts with the data. XAMPP gets Apache and MySQL running, so the connection can actually work.