I am designing an ERP like app for a local martial arts studio. Currently, the main functionality is to keep attendance records to training sessions. To do so, I have designed the following data model:
Some relations are:
- A martial art practitioner can practice more than one martial art. But they must practice at least one martial art (I couldn't express the latter in my diagram).
- An instructor for a given martial art must be chosen among the practitioners of that martial art.
- In order to be counted as present or absent in a training session, a student should have had registered for that training session slot beforehand.
This is my first data model, so I am guessing that I have at least a couple of mistakes here. Could you please point out my mistakes here, if any?