So a staff (which is a teacher) can teach a specific subject (curriculum) to a specific class (class_id).
As you can see 'teaches' is the table where all the tables meet. I've tried the Dali tool and it did a pretty good job, by producing something like this (The 'Staff' entity, not entirely quoted, just the parts which have to do with 'teaches'):
But this makes problem when I want to persist a new Staff object, which 'teaches' a specific subject (year, class, subject_id) to a specific class_id, because it doesn't know which class_id with which subject go together. Could you please help me with a better solution for this?