Little Counter: Keep track of user accesses to site pages in MySQL

This is a simple class that keeps track of the accesses of users to the pages of a site using a MySQL table to record the user access hits.

The class connects to the MySQL database and records in the counter table the IP address of the user accessing the site and the current time. The class assumes that each IP address corresponds to one user.

The class is also able to query the counter table and retrieve:

1) The total number hits
2) The total number of visits
3) The number of users, which are online. A user is considered to be online if he has accessed to the site within a period of time defined by the class variable online time.
4) The number of hits of one user during the last 24 hours