Firebase Android, checking if an object (with multiple children) exists

Question

I am using a Firebase Database to store user’s reports. Each user is allowed to submit only 10 different reports.

In the example below we have a user named “Jasna Kulja

Answer 1

Firebase queries can only order/filter by a single property. So there is no WHERE clause within Firebase. What should you do instead, is to couple a compound value named location_mode_spinnerOne. Your database structure should look like this:

Firebase-root
   |
   -- Students Reports
         |
         -- Jasna Kuljancic
               |
               -- Clinical First
                     |
                     -- -KuVRQ4OjdfKXCNdLWzb
                            |
                            --- data: 3939393
                            |
                            --- location: "fifififi"
                            |
                            --- mode: "ododododo"
                            |
                            --- spinnerOne: "Asylum Hill Family Clinic"
                            |
                            --- location_mode_spinnerOne: "fifififi_ododododo_Asylum Hill Family Clinic"

As you probably see, i have added the new compound value location_mode_spinnerOne for each particular category. This means that you can query your Firebase database according to this new location_mode_spinnerOne field. Assuming that the above database structure is correct, please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference categoryRef = rootRef.child("Students Reports").child(fullname).child(CATAGORY);
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        String searchedText = "fifififi";

        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String location_mode_spinnerOne = ds.child("location_mode_spinnerOne").getValue(String.class);
            if(!location_mode_spinnerOne.contains(searchedText)) {
                categoryRef.child(uniqueID).setValue(subreport);
            }
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
categoryRef.addListenerForSingleValueEvent(eventListener);

I gave you an example for searching fifififi keyword. The searchedText text would be the exact searched text typed by the user.

To better understanding, i suggest you see this tutorial.