Consider the relation Courses(C, T, H, R, S, G), whose

attributes may be thought of information as course, teacher, hour, room,

student, and grade. Let the set of FD’s for Courses be C->T, HR -> C, HT -> R, HS -> R, and CS -> G. Intuitively, the first says that a course has a unique teacher, and the

second says that only one course can meet in a given room at a given hour. The

third says that a teacher can be only one room at a given hour, and the fourth

says that the same about students. The last says that students get only one

grade in a course.

Let’s choose the key of Courses?