Firebase query ordering not working properly - swift

Question

Basically I have played with Firebase for the past week, and I recently stumbled upon the 'queryOrderedByChild()' that as far as I know - allows you to sort data in firebase. However, I seem to not get the proper results. My Firebase data looks like this:
{
"names" : {
"-KHVUwXdVPHmrO_O5kil" : {
"id" : "0",
"name" : "Jeff"
},
"-KHVV7lCeac0cZNMi9fq" : {
"id" : "3",
"name" : "Stig"
},
"-KHVVCjXgl0XxasVOHF1" : {
"id" : "13",
"name" : "Ali"
},
"-KHVVJtyUO-yJZiompJO" : {
"id" : "7",
"name" : "Hannah"
},
"-KHVVR8tMSO1Oh7R8tR1" : {
"id" : "2",
"name" : "Amanda"
}
}
}
, and my code looks like this:
ref.childByAppendingPath("names")
.queryOrderedByChild("id")
.observeEventType(.ChildAdded) { (snapshot:FDataSnapshot!) in
if let myID = snapshot.value["id"] as? String {
print(myID)
}
The output is still in a random order, displaying: 0, 2,7,1,8,4 - Isn't this supposed to be numeric? What am I doing wrong? How can I sort it so it get's numeric either ascending or descending?

Answer 1

You say that you're ordering by a number, but the value of your id property is stored as a string.
Since you're storing them as a string, they will be returned in lexicographical order.
If you want them to be in numerical order, you should store them as numbers
"-KHVUwXdVPHmrO_O5kil" : {
"id" : 0,
"name" : "Jeff"
},
Alternatively, you could store the ids as zero-padded strings:
{
"names" : {
"-KHVUwXdVPHmrO_O5kil" : {
"id" : "0000",
"name" : "Jeff"
},
"-KHVV7lCeac0cZNMi9fq" : {
"id" : "0003",
"name" : "Stig"
},
"-KHVVCjXgl0XxasVOHF1" : {
"id" : "0013",
"name" : "Ali"
},
"-KHVVJtyUO-yJZiompJO" : {
"id" : "0007",
"name" : "Hannah"
},
"-KHVVR8tMSO1Oh7R8tR1" : {
"id" : "0002",
"name" : "Amanda"
}
}
}
Since the strings are all the same length, they will be sorted in the correct order. But you'll have to decide on the length of the string/maximum id value in the latter solution, so it seems worse.

Answer 2

If you using order by child you going to order your id you no going to touch it's value.
Then maybe you have to try something like
(FIRDatabaseQuery *) queryOrderedByValue
queryOrderedByValue: is used to generate a reference to a view of the data that's been sorted by child value.