firebase real time dB retrieving of specific data from multiple users in swift

Question

so I'm working this days on a new project and I have problem I couldn't solve, I hope someone can help me. I'm working on iOS app and storing all the user data on Firebase Real time dB . my main goal is to get specific data from all users from specific position, for example: inside users, I have different uID's of all the users in the dB. in each one of them there is username, I would like to retrieve the username of all Users. in the future I would like to store location for each user under "Location". I would like to get all users that they're location is "New-York". I'll be glad to get some ideas how to figure it out! Thanks!

users

  XLS37UqjasdfkKiB
      username: "Donald"

  ei8d4eYDafjQXyZ
      username: "Barak"

  etcj0lbSX5Oasfj
      username: "Abdul"

  rglmlG6Rasdgk5j
      username: "Ron" 

Answer 1

You can:

1. Load all JSON from /Users.
2. Loop over snapshot.children.
3. Then get the value of each child's username property.

These are also the most common navigation tactics when it comes to Firebase Realtime Database, so you'll apply these to pretty much any read operation.

Something like this:

Database.database().reference().child("isers").observe(.value, with: { (snapshot) in
    if !snapshot.exists() {
         print("No users found")
    } else {
        for case let userSnapshot as DataSnapshot in snapshot.children {
            guard let dict = userSnapshot.value as? [String:Any] else {
                print("Error")
                return
            }
            let username = dict["username"] as? String
            print(username)
        }
    }
})

Also see:

• the documentation on reading data.
• the documentation on listening for lists of data with a value event.
• How to properly use queryOrderedByValue
• Get Children of Children in Firebase Using Swift
• And more from searching on [firebase-realtime-database][swift] children.