就我而言，哪种Firebase数据结构行为最佳？

Question

We are creating an app where the teacher can create his class register, and it should look like that: Teacher creates his profile, after that there is an activity with RecyclerView that displays students names. Below RecyclerView there is TextView that says "Student! create your own profile" (ofcourse after clicking it, there is an activity for creating students profile). Student can create his profile only by using the same device as teacher while he was creating Teachers Profile. Ok, that looks nice and so far we have it all done, but here comes our question. What is the best behaviour to store users data in this case? Should we structure our data this way?

{
  "Teachers" : {
    "USYSacnOjDR5EAPwljZMHtggN9I2" : {
      "teachername" : {
        "teachername" : "Janis"
      },
        "students" : {
          "0xgMzfOLLwQ2KWF7aKhH5ZIbQnx2":{
            "studentname": "Pavel"

         }
      }
    }
  },

So, this looks like veeery badly structured data, we know it, but like we said before, We need to display in RecyclerView the names of this specific teacher students that are other FirebaseAuth users and had their own datas like grades Every opinion or critique is appreciated.

@Edit here is how i retrieve data :) reference=FirebaseDatabase.getInstance().getReference("teachers").child(teacherkey).child("users");

 reference.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                User user = dataSnapshot.child("name").getValue(User.class);
                result.add(user);
                adapter.notifyDataSetChanged();
            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

                User user = dataSnapshot.child("name").getValue(User.class);
                result.remove(user);
                adapter.notifyDataSetChanged();
            }

Answer 1

According to your comment, a possible database structure can be this:

Firebase-root
   |
   --- teachers
   |     |
   |     --- teacherIdOne
   |     |      |
   |     |      --- "teacherName" : "Teacher Name One"
   |     |      |
   |     |      --- students:
   |     |             |
   |     |             --- studentIdOne: "Student Name One"
   |     |             |
   |     |             --- studentIdTwo: "Student Name Two"
   |     |
   |     --- teacherIdTwo
   |            |
   |            --- "teacherName" : "Teacher Name Two"
   |            |
   |            --- students:
   |                   |
   |                   --- studentIdThree: "Student Name Three"
   |                   |
   |                   --- studentIdFour: "Student Name Four"
   |
   --- students
         |
         --- studentIdOne
         |      |
         |      --- "studentName" : "Student Name One"
         |
         --- studentIdTwo
         |      |
         |      --- "studentName" : "Student Name Two"
         |
         --- studentIdThree
         |      |
         |      --- "studentName" : "Student Name Three"
         |
         --- studentIdFour
         |      |
         |      --- "studentName" : "Student Name Four"
         |
         --- studentIdFive
                |
                --- "studentName" : "Student Name Five"

And to display all 5 students name, please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference studentsRef = rootRef.child("students");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String studentName = ds.child("studentName").getValue(String.class);
            Log.d("TAG", studentName);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
studentsRef.addListenerForSingleValueEvent(valueEventListener);

Te output will be:

Student Name One
Student Name Two
Student Name Three
Student Name Four
Student Name Five

If you are interested in displaying those names into a RecyclerView , this is how you can retrieve data from a Firebase Realtime database and display it in a RecyclerView using FirebaseRecyclerAdapter .

If you want to display the student of a particular teacher, please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference studentsRef = rootRef.child(teachers).child(teacherId).child("students");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String studentName = ds.getValue();
            Log.d("TAG", studentName);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
studentsRef.addListenerForSingleValueEvent(valueEventListener);

In which the teacherId is the id of the teacher you want to display its students. If the id of the teacher is for example teacherIdOne , the output will be:

Student Name One
Student Name Two