Database connection failed

Hi. This is my first question about websites. I have been trying hard to understand how to setup WordPress for my site http://watchingprice.com
I created database, gave it an username and a password. But after filling these information into the wp-config.php file, the site always says connection failed. I’m very sure that the username and password i entered correctly, but still somehow it cannot work.

I’d like to ask how to fix this problem?

Thank you.