How to Update Particular Value of Child in Firebase Db

Firebase how to update child value in javasscript

2 problems:
1.You forgot to add "\eventos" on you child path.
2.dont use .set(), because it will delete all the other data.
Instead of .set() use .update().
Try this code:

firebase.database().ref('usuario')
                    .on('value',event =>{
                        event.forEach(user =>{
                            user.child('eventos').forEach(evento =>{
                                if (evento.val().categoryId === payload.id){
                                  //Here is where i try to update the childe value, in my case category
                                    let ref = firebase.database().ref('usuario/'+user.key+'/eventos/'+evento.key+'/'+evento.val().category)
                                        .update(payload.name)
                                    console.log(ref)
                                }

                            })
                        });

                    });

Let me know if it still dont work

Is it possible to update only specific data on my child on firebase?

Yes it is possible:

FirebaseUser user=FirebaseAuth.getInstance().getCurrentUser();
String useruid=user.getUid();
DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Accounts").child("user").child(useruid);
ref.child("date").setValue(newdate);
ref.child("email").setValue(newemail);
ref.child("name").setValue(newname);
ref.child("type").setValue(newtype);

If you have the list of names in a listview and you want to update them then, you can do the following:

listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
final String selectedFromList = (String) listview.getItemAtPosition(position);
DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Accounts").child("user").child(useruid);
ref.orderByChild("name").equalTo(selectedFromList).addValueEventListener(new ValueEventListener(){
 @Override
 public void onDataChange(DataSnapshot dataSnapshot) {

  //update values here
     }
  }

   @Override
 public void onCancelled(FirebaseError firebaseError) {

            }
        });
    });

How to update value of a particular child node in firebase realtime database?

Please note that Firebase database does not accept null values, so if you try to update a node with anything that results in null value, the node will be deleted. For more information, please check the documentation on https://firebase.google.com/docs/database/admin/save-data

I'm not sure if that is the reason behind your issue, I would need more information on what updatedPrice is, but try to log this variable and examine its contents, maybe it is resolving as a null value and causing the error.

Good luck!

How to update particular value of child in Firebase DB

For Updating values at a particular node in Firebase Realtime Database, use:-

• You can either use runTransactionBlock:

    func updateTotalNoOfPost(completionBlock : (() -> Void)){
  
  let prntRef = FIRDatabase.database().reference().child("komal_kyz").child(your_AuroID).child("dealResul")
  
  prntRef.runTransactionBlock({ (resul) -> FIRTransactionResult in
      if let dealResul_Initial = resul.value as? Int{
  
          //resul.value = dealResul_Initial + 1
          //Or HowSoEver you want to update your dealResul. 
           return FIRTransactionResult.successWithValue(resul)
      }else{
  
          return FIRTransactionResult.successWithValue(resul)
  
      }
      }, andCompletionBlock: {(error,completion,snap) in
  
              print(error?.localizedDescription)
              print(completion)
              print(snap)
          if !completion {
  
             print("Couldn't Update the node")
          }else{
  
              completionBlock()
          }
      })
  
   }
  

  While calling this function:-

  updateTotalNoOfPost{
         print("Updated")
        }
  

• Or just call updateValues

      let prntRef  = FIRDatabase.database().reference().child("komal_kyz").child(your_AuroID)
      prntRef.updateChildValues(["dealResul":dealResult]) 
  

PS:- Prefer using runTransactionBlock: instead of .updateChildValues if you only want to increment a particular node. Also read this: -https://stackoverflow.com/a/39458044/6297658

How can I change the value of child in Firebase database?

If you've got the DataSnapshot for a path in the database, it's easy to get the DatabaseReference that you need to update it:

DatabaseReference reference = FirebaseDatabase.getInstance().getReference("BetSlip");
reference.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot snapshot) {
        for (DataSnapshot ds: snapshot.getChildren()) {
            String timestamp = ""+ ds.child("timeStamp").getValue();
            String toggleStatus = ""+ ds.child("toggleStatus").getValue();
            if (timeStamp.equals(timestamp) && toggleStatus.equals("on")) {
                ds.child("toggleStatus").getRef().setValue("off");
            }
            if (timeStamp.equals(timestamp) && toggleStatus.equals("off")) {
                ds.child("toggleStatus").getRef().setValue("on");
            }
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError error) {
        throw error.toException(); // never ignore errors
    }
});

Since you're updating the node based on its existing value, strictly speaking you might need to use a transaction for it.

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