General help

Hello everybody,

I am to start my first server with Moodle for my company. Moodle is a great platform with many features and a very active community (I've submitted some bugs with the 1.5 version and appreciated very much the time to solve the bugs).

I've taken a lot of time reading docs and forum but I did'nt get the answer to my question.

On our site, we want to sell courses (nothing hard up to this point). The approach is the following :

• a course is defined by a given expected duration in hours ( ex : 1.5 hours for one course, or 40 hours for an other one).
• a student may take N times this time to complete it (N is an estimated value varying between 1 to 5 and can vary from one course to the other one)
• when the online time is over, the student is automatically unenrolled from the course.
• the course can be directly built up in Moodle, or a SCORM 1.2 package.
  

Of course, I know it's hard to determine the "on-line time" (I read carefully the doc of the "register" plugin) unless you trust information provided by the client navigator.

So, my question is : could you tell me which tables/fields contain information relative to the on-line time, and how to handle them in order to meet the goal (auto-unenroll) ?

TIA

PS : the Moodle release is 1.7.1+, with PHP 5.2 and MySQL 4.20.