database open close procedure

This program is great. Some info on databases though.

Is the program written so that database access is kept to a brief time by good code writing (I imagine it must be since this program is so great) but I am asking because of the access limit of concurrent users.

I notice I am still logged in even when I come back to the websoite after quite a while. Does this mean the datbase has been left open or just a session variable and so databse is actually closed?