Log Writer and Reader: Store and retrieve logs from a MySQL database

This class can be used to store and retrieve activity logs from a MySQL database.

It can add new activity log records into a given MySQL table. It can log details like the type of log reference, an error message, the HTTP referrer URL, the remote user address, the logged user identifier, etc..

The class can also do the opposite, i.e., retrieve log entries from the database table and return it as an array.