Looking connection

Hello,

I wanted to know which is the path of PHP that makes the connection to the database, I found the configuration file but not where the connection is made to the database.

In my piwik I want to enter “index.php” make a statement to the database and check if a user ID (which I receive otherwise) exists in the piwik database, if so it will return the password in MD5 and he passeth the route to “auto login” as it says here [piwik.org]

( My first post is in the wrong place, now in the correct forum )