should parent entity always have a primary key? I am have 3 entities, Person(fname, lname) none of them is primary, then User(email, password) and Receptionist(emp_id) bold is primary key. I have extended there two entities from Person, total participation and overllapping, so person must be either user or receptionist or both at the same time. Is it okay if I do not use primary key in Person
How can you identify each record if you don't have primary key. What if there is person having the same name and use it for future data. You must have primary key for table Person.