Hi, I have been watching the forums in the past few days. Nice to see people have some questions. I clarified some questions today in the class and later by individual appointments. First of all you need to state your assumptions. After interaction with multiple students, here are some of the ways that you can approach the terms mentioned in the case study. "Each eye surgeon has one or two minor surgeries in which they work". Some of you are considering minor surgery as a service. This could work, but remember that in such clinics, surgery is often referred to as a "surgery room" as indicated in the case study "...in which they work". Just state your assumption when you are referring to this term. "a parent might be a customer without being a patient if they pay the bills for their child who is a patient." Hint: One option is to do specialisation here. For instance for a class person, you can have two subclasses, patient and customer. You need to think of how you are going to apply constraints. "the patient cannot have multiple appointments with the same surgeon on the same day" Hint: Think of how you can make a tuple unique. Treatment vs Service. Hint: Assume eyesight-check is a treatment, it may offer finding the right power for the classes and may also offer fitting contact lenses. Cheers Mehwish

Never would I expect a "surgery" refers to a room, given the fact that the only expression in the sheet which explicitly talked about rooms is "treatment rooms", and it appears way before "surgery". I thought there should be some consistency when we are using terms. Oh, and you have said we can "for example, assume surgery is a special service, it makes sense" during a workshop, which makes things worse. Thank you for clarifying everything here finally, but many students have already been working on their projects, and some may have even completed most of their work since the deadline is approaching. It would surely be disappointing for them to discover that they have misunderstood the instructions...