A school has a name. Teachers work there and students attend classes. Students and teachers have in common that their first and last names are recorded. Teachers' email addresses are also known. Students attend exactly one school, whereas a teacher can teach at a maximum of three schools. The number of hours for each such teaching relationship is known. Each school has exactly one principal, who is chosen from among the teachers. Although a teacher can teach at several schools, they can only be the principal of one school.
In addition to the people working at the school, it also consists of a large number of rooms. These can be classrooms with a name and capacity, or other rooms such as a gym, which also have a name and a size specification in square meters. Between 10 and 31 students form a class group, which has a name (e.g., 5a). A student is always in exactly one class group. A class group is assigned to exactly one classroom and vice versa.