Swift Firebase -How to Update a Value at multiple refs?

Question

When a user first creates an account I check to see if the username they pick is available underneath all_usernames ref which is just a pool of all the users names. If the name isn't in there I add their userId and username to that ref (so no other users can pick it) and I also add it underneath the users ref (this is where their profile photo, username, etc would be for posts)

-all_usernames
   |
   @--userId // kim_k's uid
       |
       |----username: "kim_k"

-users
   |
   @--userId // kim_k's uid
        |
        |---username: "kim_k"
        |---profileURL: "https//..."
        |---age: 27

My app has a followers and following ref. I have a searchBar where users can search for people who are following them by name.

Everything works fine but I ran into hiccup. Let's say the user they are following is "kim_k".

let searchText = searchController.searchBar.text?.lowercased() // "kim_k"

let currentUserId = Auth.auth().currentUser!.uid // a different user

followingRef.child(currentUserId)
    .queryOrdered(byChild: "username")
    .queryStarting(atValue: searchText)
    .queryEnding(atValue: searchText+"\u{f8ff}")
    .observeSingleEvent(of: .value, with: { (snapshot) in ... }

Using the code above the currentUser who is performing the search will find "kim_k" underneath their following ref. So will Jill and Jane (separate users) if they were to search for her name underneath their ref (the lat/lon locations are necessary for a separate reason):

-following
    |
    @--userId // currentUserId
    |    |
    |    @----userId // kim_k's uid
    |           |
    |           |----username: "kim_k"
    |           |----lat: 0.111
    |           |----lon: 0.222
    |
    |
    @--userId // jill's uid
    |    |
    |    @----userId // kim_k uid
    |           |
    |           |----username: "kim_k"
    |           |----lat: 0.333
    |           |----lon: 0.444
    |
    @--userId // jane's uid
         |
         @----userId // kim_k's uid
                |
                |----username: "kim_k"
                |----lat: 0.555
                |----lon: 0.555

The hiccup is what happens if "kim_k" changes her name to "kim_kardashian"?

If she were to change it it would be updated under the users ref and the all_usernames ref. When the currentUserId, Jill, and Jane search for her it would return her old username.

The "kim_kardashian" name change would have to happen at the users ref, all_usernames ref, following ref, and the followers refs.

How can I fix this?

Answer 1

To answer the question

Swift Firebase -How to Update a Value at multiple refs?

Updating multiple refs is easy. Suppose you have a structure

items
   item_0
      item_name: "some item 0"
   item_1
      item_name: "some item 1"

and you want update both item names. Here's the swift code.

func updateMultipleValues() {
    let path0 = "items/item_0/item_name"
    let path1 = "items/item_1/item_name"

    let childUpdates = [ path0: "Hello",
                         path1: "World"
    ]

    self.ref.updateChildValues(childUpdates) //self.ref points to my firebase
}

and the result is

items
   item_0
      item_name: "Hello"
   item_1
      item_name: "World"

EDIT

There are acutally a couple of questions going on here so the above specifically shows how to update multiple refs at one time. However, that's actually unrelated to what the actual issue is.

Don't store user names in multiple places (for this use case). There are times whan that's needed (denormalizing) but not here.

The 10,000' view is as follows

If I want to know the names of the users who are following the current user, here's a start.

/users
   uid_0 //assume this is the logged in user
      name: "My Name"
      followers
         uid_1 //uid_0 is being followed by uid_1
            some data
         uid_2
            some data
      following
         uid_3
  uid_1
      name: "Some other user name"
      followers
         whoever is following this user
      following
         uid_0 //uid_1 is following uid_0

then to get the names of who is following the the logged in user we'll use some pseudo code to keep it short.

let myFollowerNode = firebase.users.myuid.followers //read in the followers node
myFollowerNode.observeSingleEvent(.value, with { snapshot in
    //get the array of keys from the snapshot which would be
    let userIdArray = keys(snapshot)
    //  uid_1
    //  uid_2
    for uid in userIdArray { //iterate over the uid's, reading in their names
       let aUser = firebase.users.uid.name
       aUser.observeSingleEvent(.value..... 
           let name = snapshot.value as! string //that users name