//Update information about a course
    public void setCourseInfo(String iD, JTextField newCourseName, String newCourseStart, String newCourseEnd, JComboBox newTeacher, JComboBox newSubject) {
    try {
            //Name of the new course
            String course = newCourseName.getText();
            //Dates
            DateFormat format = new SimpleDateFormat("yyyy-MM-d", Locale.GERMAN);
            Date startDate = format.parse(newCourseStart);
            DateFormat format2 = new SimpleDateFormat("yyyy-MM-d", Locale.GERMAN);
            Date endDate = format2.parse(newCourseEnd);
            //New id
            String tempTeacher = newTeacher.getSelectedItem().toString();
            String[] splitStr = tempTeacher.split("\\s+");
            String teacherId = getIdTeacher(splitStr[0], splitStr[1]);
            //get subject Id for course
            String courseSubject = newSubject.getSelectedItem().toString();
            String subjectId = getSubjectId(courseSubject);
            //The accual command to insert new course
            String command = "UPDATE kurs SET kursnamn= '" + course + "', kursstart= '" + startDate + "', kursslut= '" + endDate + "', kurslarare= " + teacherId + ", amnestillhorighet= " + subjectId +
                    "WHERE kurs_id=" + iD;
            hwdb.insert(command);
        } catch (InfException e) {
            System.out.println(e.getMessage());
        } catch (ParseException er) {
            System.out.println(er.getMessage());
        }
    }

    //Remove a course from the system
    public void deleteCourse(JComboBox courseName) {
        try {
            //Get courseId from a coursename in a combobox
            String course = courseName.getSelectedItem().toString();
            String command = "SELECT kurs_id FROM kurs WHERE kursnamn= '" + course + "'";
            String courseId = hwdb.fetchSingle(command);
            //Delete course from various places
            String command1 = "DELETE FROM har_betyg_i WHERE kurs_id=" + courseId;
            hwdb.delete(command1);
            String command2 = "DELETE FROM registrerad_pa WHERE kurs_id=" + courseId;
            hwdb.delete(command2);
            String command3 = "DELETE FROM kurs WHERE kurs_id=" + courseId;
            hwdb.delete(command3);
        } catch (InfException e) {
            System.out.println(e.getMessage());
        }
    }