On all the subjects of the student the same grade is retrieved, the grade of the first subject is repeated in the other subject grades. I know the problem is in the hashmap that I have defined for subjects so what changes do I need to do there for this problem to be fixed.
Here is what it looks like:
Here is the method that the GET REQUEST calls:
public Student getStudentById(int id) throws Exception {
Connection connection = null;
Student student = new Student();
student.setSubjectList(new ArrayList<>());
Map<String,Subject> subjectMap = new HashMap<>();
Map<String,StudentMark> markMap = new HashMap<>();
try {
connection = new MysqlDbConnectionService().getConnection();
String select = "SELECT s.user_id, s.username, s.password, s.fullname, s.email,subj.id, subj.name, f.fid, f.university_id," +
" f.fname,p.professor_id, p.first_name,p.last_name,p.title, g.grade_id, g.mark, g.description " +
" FROM student s " +
" INNER JOIN student_faculty sf ON sf.student_id=s.user_id\n" +
" INNER JOIN faculty f ON sf.faculty_id=f.fid\n" +
" INNER JOIN faculty_subject fs ON f.fid = fs.faculty_id\n" +
" INNER JOIN subject subj ON fs.subject_id = subj.id\n" +
" INNER JOIN professor_subject ps ON ps.subject_id = subj.id\n" +
" INNER JOIN professor p ON ps.prof_id = p.professor_id\n" +
" INNER JOIN student_subject_marks sm ON sm.student_id = s.user_id\n" +
" INNER JOIN student_subject_marks ds ON ds.subject_id = subj.id\n" +
" INNER JOIN grade g ON sm.grade_id = g.grade_id\n" +
"WHERE user_id = ?";
PreparedStatement ps = connection.prepareStatement(select);
ps.setInt(1, id);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
if(student.getId()==null) {
student.setId(rs.getString("user_id"));
student.setUsername(rs.getString("username"));
student.setPassword(rs.getString("password"));
student.setFullName(rs.getString("fullname"));
student.setEmail(rs.getString("email"));
}
String subjectID=rs.getString("id");
Subject subject =null;
Professor professor=null;
StudentMark mark = null;
if(!subjectMap.containsKey(subjectID)) {
subject=new Subject();
subject.setId(rs.getInt("id"));
subject.setName(rs.getString("name"));
subject.setProfessorList(new ArrayList<>());
subject.setMarkList(new ArrayList<>());
subjectMap.put(subjectID, subject);
professor = new Professor();
professor.setProfessor_id(rs.getInt("professor_id"));
professor.setFirst_name(rs.getString("first_name"));
professor.setLast_name(rs.getString("last_name"));
professor.setTitle(rs.getString("title"));
mark = new StudentMark();
mark.setGrade_id(rs.getInt("grade_id"));
mark.setMark(rs.getInt("mark"));
mark.setDescription(rs.getString("description"));
subject.getProfessorList().add(professor);
subject.getMarkList().add(mark);
}
else{
subject = subjectMap.get(subjectID);
}
//
}
} catch (Exception e) {
System.out.println(e + "Retrieve not successful");
}
student.getSubjectList().addAll(subjectMap.values());
return student;
}
Here is the ER DIAGRAM:
