How to check for duplicate data in firebase
I am using firebase. I want to check for duplicate data for my application. I am currently allowing the user to enter a name and email address. But if the user enters the same name and email a second time, it is also added to the database. how to solve this problem Here is my code:
package com.example.zaid_pc.mpd2;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
public class tournament extends AppCompatActivity {
private EditText etTournament;
private EditText emailTournament;
private DatabaseReference mDatabaseRefernce;
Button btnTournament;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tournament);
etTournament = (EditText)findViewById(R.id.etTournament);
emailTournament = (EditText)findViewById(R.id.emailTournament);
btnTournament = (Button)findViewById(R.id.btnTournament);
mDatabaseRefernce = FirebaseDatabase.getInstance().getReference().child("People Registered");
btnTournament.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String name = etTournament.getText().toString().trim();
final String email = emailTournament.getText().toString().trim();
//mDatabaseRefernce.child("Name").setValue(name);
//mDatabaseRefernce.child("Email").setValue(email);
final DatabaseReference peopleRegisered = mDatabaseRefernce.push();
peopleRegisered.child("Name").setValue(name);
peopleRegisered.child("Email").setValue(email);
Toast.makeText(tournament.this, "You will be notified via email", Toast.LENGTH_LONG).show();
finish();
}
});
}
}
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Before transferring data to the database, first check with the database if the data exists or not
check username or not from following code
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference.child("issue").orderByChild("id").equalTo(0);
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
// dataSnapshot is the "issue" node with all children with id 0
for (DataSnapshot issue : dataSnapshot.getChildren()) {
// do something with the individual "issues"
}
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
changed this code based on your needs
for link Firebase Request Data
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To solve this problem, I recommend that you use a unique ID for each user. This identifier can be a unique identifier generated by the method push()
, uid
or email address
. I offer you the last option. Since Firebase does not accept a character, for example .
in a key, you need to set up your email address like this:
name@email.com → name @email, com
To achieve this, let's look at two methods to help you encode
and decode
provide an email address.
private String encodeUserEmail(String userEmail) {
return userEmail.replace(".", ",");
}
private String decodeUserEmail(String userEmail) {
return userEmail.replace(",", ".");
}
Assuming the database structure looks like this:
root
|
--- users
|
--- name@email,com
|
--- uid: 4362454274745
|
--- name: John
you can check if the user exists using the following code:
DatabaseReference userEmailRef = FirebaseDatabase.getInstance().getReference().child("users").child(userEmail);
ValueEventListener valueEventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
Log.d("TAG", "Users exists!");
} else {
//Create user
}
@Override
public void onCancelled(DatabaseError databaseError) {}
};
userEmailRef.addListenerForSingleValueEvent(valueEventListener);
In which userEmail
is the encoded email of the user.
Hope it helps.
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I understand how below code you need to add one value sink here and check if the data you want to look for in the table exists or not.
mFirebaseDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(final DataSnapshot dataSnapshot) {
for (DataSnapshot data : dataSnapshot.getChildren()) {
//If email exists then toast shows else store the data on new key
if (!data.getValue(User.class).getEmail().equals(email)) {
mFirebaseDatabase.child(mFirebaseDatabase.push().getKey()).setValue(new User(name, email));
} else {
Toast.makeText(ChatListActivity.this, "E-mail already exists.", Toast.LENGTH_SHORT).show();
}
}
}
@Override
public void onCancelled(final DatabaseError databaseError) {
}
});
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