Getting data range from firebase with swift - swift

Question

I would like to ask that question. The question is how to get specific data range from firebase ?
I have table on firebase like this:
"users" : {
"Jz3IpatRWiWoDbiYM62q6qbHB503" : {
"email" : "Kaanozdemir#gmail.com",
"lastName" : "Ozdemir",
"name" : "Kaan"
},
"PmeYYFiac0c55fU2sFpnTP308mC3" : {
"email" : "kevinhart#gmail.com",
"lastName" : "Hart",
"name" : "Kevin"
},
"r0bMqSGCWihFi2EF4u6ckSzLP8v1" : {
"email" : "Marcusalvarez#gmail.com",
"lastName" : "Alvarez",
"name" : "Marcus"
},
"A3tmSSGCWihFi2EF4u6ckSzLP8c1" : {
"email" : "taylorswift#gmail.com",
"lastName" : "Swift",
"name" : "Taylor"
},
"3SUTsiGCWihFi2EF4u6ckSzLP8v2" : {
"email" : "jimmyfellon#gmail.com",
"lastName" : "Fellon",
"name" : "Jimmy"
},
"lgSit3GCWihFi2EF4u6ckSzLP8u3" : {
"email" : "jaxteller#gmail.com",
"lastName" : "Teller",
"name" : "Jax"
}
For example, I would like to get users values between 2 and 4 [2 - 4](Marcus Alvarez - Taylor Swift - Jimmy Fellon).
Is there any way to do that server side ? I don't wanna get all data and pick values that I want. Anyone knows?

Answer 1

Change your JSON DB structure to include an index in every node :
"users" : {
"autoID1" : {
"email" :.....,
"lastName" : ......,
"name" :.......,
"index" : //e.g.. 1,2,3,4......
}
},
"noOfUsers" : 223,
If you are appending this users node via app, you have too keep track of the no of users in Database node users and keep updating the noOfUsers whenever a new user is added. And to set the next ones index number , just retrieve that node value i.e 223 and sees it and then increment the noOfUsers......
To retrieve between 2-4 .. Now you can use :
Database.database().reference().child("users").queryOrdered(byChild: "index").queryStarting(atValue: "2").queryEnding(atValue: "4").observe....