Question

Im stuck with this little project in C# but basically my problem is this:
Im trying to create a data structure for exam stats…
So:
one student can have many subjects
and one subject can have many students
the complicated part is that, one subjects can have multiple exams(retakes), so therefore a student will have many results for one subject…
Im kinda lost of how to normalize this. Can anyone suggest? this is my first solution:

class StudentRec
{
    string name;
    string candidate_number;
    string student_id;
    List<Subject> modules;
}

class Subject_Record
{
    string subject_code;
    Exam_Record first_attempt;
    Exam_Record second_attempt;
    Exam_Record third_attempt;

}

class Exam_Record
{
   string year;
   int mark;
   char grade;
}

however, if I did it this way,each student would have a different instance of the same subject.

Answer 1

Something like

• Student
  • name etc
• Subject
  • code etc
• Enrolment/Student-Subject (many-to-many)
  • student reference
  • subject reference
  • date of enrolment etc
• Exam (one-to-many from Enrolment)
  • enrolment reference
  • date of exam
  • mark/grade

So a Student enrols in a Subject -> Enrolment. Then for an Enrolment you can have many Exam(s), one for each sitting to handle retakes.