Querying for existing nodes in Firebase is returning null

Question

My tree structure looks like in FireBase

• BOOKS
• USERS
  • UserA_ID
  • UserB_ID
  • UserC_ID
    • UserName:@\"\"
    • UserEmai

Answer 1

A couple of things. To test for null you should really

 if (snapshot.value == [NSNull null])

Here's a slightly modified implementation of your code that includes the NSNull check.

Firebase *ref = [self.myRootRef childByAppendingPath:@"users"];

FQuery *query = [[ref queryOrderedByKey] queryEqualToValue:@"UserC_ID"];

    [query observeSingleEventOfType:FEventTypeValue withBlock:^(FDataSnapshot *snapshot) {

        if (snapshot.value == [NSNull null]) {
            NSLog(@"was null");
        } else {
            NSLog(@"key: %@    %@", snapshot.key, snapshot.value);
        }
    }];

I set up a test Firebase with the same structure you are using and it works correctly; returns null for nonexistent user id's and returns the node UserC_ID when it does.

So maybe your code that sets the userIDKey is misbehaving or perhaps your userRef is wonky.