How will the project Structure look like

Question

How will the project structure look like on FirebaseDatabase.i got it from an open source code but i cant figure it out how will this look like

FirebaseDatabase database = FirebaseDatabase.getInstance();
Query dbQuery = database.getReference("teachers-courses").orderByChild("teacherNo").equalTo(uid);

and this

dbQuery.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot courseSnapshot: dataSnapshot.getChildren()) {
            String course = courseSnapshot.child("courseNo").getValue().toString();
            courses.add(course);
        }

        // Resolve query for courses names.
        Query coursesQuery = database.getReference("courses");

        // Event listenere to update.
        coursesQuery.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for (DataSnapshot courseSnapshot: dataSnapshot.getChildren()) {
                    // Grab the key.
                    String key = courseSnapshot.getKey();
                    // If key is required.
                    if (courses.contains(key)){
                        String courseName = courseSnapshot.child("name").getValue().toString();
                        coursesName.add(courseName);
                    }
                }

                // Fill the list.
                ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
                        CourseTeacherActivity.this,
                        android.R.layout.simple_list_item_1,
                        coursesName );

                // Set the adapter.
                lv.setAdapter(arrayAdapter);
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                System.out.println("The read failed: " + databaseError.getCode());

            }
        });
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        System.out.println("The read failed: " + databaseError.getCode());
    }
});

this is a source code from github and was trying to figure it out for days now but i cant seem to figure it out i will appreciate if you can show me what the project structure would look like in Firebase Database thank you in advance

do you mean the database's structure? – Ticherhaz FreePalestine May 23 '20 at 14:33 — Ticherhaz FreePalestine, May 23 '20 at 14:33
@Ticherhaz yes i mean the structure – Tripping May 23 '20 at 14:34 — Tripping, May 23 '20 at 14:34

score 0 · Accepted Answer · answered May 23 '20 at 14:36

The code you shared seems to load the courses for a specific teacher, but first loading the course IDs for that teacher, and then loading the course data.

Let's see what we can determine about the JSON structure from the code:

The database.getReference("teachers-courses").orderByChild("teacherNo").equalTo(uid) indicates:
1. That there is a child teachers-courses under the root.
2. That each child node under there has a property teacherNo with a UID as its value.
3. This typically means that the nodes directly under teachers-courses use a push ID as their key.
The courseSnapshot.child("courseNo").getValue().toString() then shows that each child node has a courseNo property.
The database.getReference("courses") shows that there's another top-level node courses that contains the courses. At this point it becomes clear that we have a fairly standard many-to-many relationship, as for example explained here: Many to Many relationship in Firebase
The courseSnapshot.getKey(); indicates that the key for each node under /courses is the ID for that course.
The courseSnapshot.child("name").getValue().toString() shows that each course has a name property.

All of this combined brings us to the following JSON:

"teachers-courses": { // 1.1
  "somepushid": { // 1.3
    "teacherNo": "someteacherid" // 1.2
    "courseNo": "somecourseid" // 2
  }
},
"courses": { // 3
  "somecourseid": { // 4
    "name": "The name of the course" // 5
  }
}

There is likely to be more data in the database, but this is what is being used by the code you shared.

How will the project Structure look like

1 Answers1