learning-unlimited/ESP-Website — comment on commit 102c0153df413ace9667174d9d6dc9ee8c449560
File:  line 0
By pricem:

As I recall, enrolled_students is an actual database column that is updated whenever the cache for ClassSection.num_students() is flushed. I'm not precisely sure though. I think the point was to make it so you could select the enrolled_students column from the database at any time and get a correct answer.