Monitor database usage?

I’m a postdoc, and I’m using DTPO with a class that I’m teaching this semester: I’ve got a database filled with relevant news clippings and links, and students will use the web interface to do some research/find potential readings. However, I can’t leave the database available to them 24/7, and it’ll be shut down before I leave campus every day. However, I wouldn’t want to prematurely cut off someone who’s actually using the database.

Is there any way to monitor the usage of the database? Specifically, is there any way for me to tell whether anyone is accessing it at a given moment, and even what files they’re accessing? The preferences pane for the server has a link to the logfile, but I don’t speak webserver and can’t tell whether it might be giving me the information I need or not.