Looping through firebase unique keys and adding data to each - firebase

Question

I have firebase database in this form.
"items":{
"-Jp9VLYBwENfNVLKYyCG" : {
"-Jp9VMKkTUggcMrUCO8S" : {
"author" : "facebook:#########",
"created" : 1431474107638,
},
"-Jp9VobJP0qbSbbEdyW0" : {
"author" : "facebook:#########",
"created" : 1431474227548
}
},
"-JpEbifKeRj-_H7TWhQ2" : {
"-JpEbrnT6SFRFc6U_HWX" : {
"author" : "facebook:#########",
"created" : 1431559961683
},
"-JpEby5mZuQMsU-9YCpk" : {
"author" : "facebook:##########",
"created" : 1431559987495
}
}
}
I want to add the following object to each $id containing author and created key-value pairs.
upVote: {
active: true,
total: 0
},
downVote: {
active: true,
total: 0
}
I am first trying to fetch the values using DataSnapshot. But it doesn't print the keys in console. What is wrong here?
var ref = new Firebase(FBURL + "/items");
ref.once("value", function(snapshot) {
console.log("snapshot key: " + snapshot.key());
snapshot.forEach(function(childSnapshot){
var key = childSnapshot.key();
var val = childSnapshot.val();
console.log("child snapshot key: " + key);
childSnapshot.forEach(function(deepSnap){
console.log("deep shot key: " + deepSnap.key());
});
});
});
RESOLVED The problem was that I had some security rules set up with read and write permissions. Therefore wasn't allowing me to read the element from the user scope that I was calling the script. It was one gotcha like problems.
After this step, it was easy to update the database with values:
var deepRef = ref.child(key).child(deepSnap.key());
deepRef.update({upVote: {
active: true,
total: 0
},downVote: {
active: true,
total: 0
}});