How to read all child data from firebase - swift

Question

How can i read all child data from Firebase.
let ShopRef = Database.database().reference(withPath: “ShoppingMallLst”).child(“ShoppingMall1”)
ShopRef.observeSingleEvent(of: .value, with: { (snapshot) in
if snapshot.childrenCount > 0 {
for data in snapshot.children.allObjects as! [DataSnapshot] {
if let data = data.value as? [String: Any] {
let Description = data["Description"] as? String
let Floor = data[“Floor”] as? Int
….
}
}
}
})
But how can i read the data from child "ShopPath?"

Answer 1

child "ShopPath" has type [String: [String: String]]
you can try:
let ShopPath = data["ShopPath"] as? [String: [String: String]]

Answer 2

The key to firebase is to keep data in snapshots as long as you can. So in this case instead of casting items to dictionaries, which loose ordering or arrays that get more complex as the structure gets deeper, leverage DataSnapshots.
Here's the main function to read all shops in ShoppingMall1 - similar to the code in your question.
func readMallShops() {
let ref = self.ref.child("ShoppingMallList").child("ShoppingMall1")
ref.observeSingleEvent(of: .value, with: { snapshot in
let allShopsSnap = snapshot.children.allObjects as! [DataSnapshot]
for shopSnap in allShopsSnap {
let shop = ShopClass(withSnap: shopSnap)
}
})
}
Then a class that holds data about each shop. Note that I pass each snapshot in to initialize the class
class ShopClass {
var name = ""
var height = ""
convenience init(withSnap: DataSnapshot) {
self.init()
let name = withSnap.childSnapshot(forPath: "ShopName").value as? String ?? "No Shop Name"
print("Shop: \(name)")
self.name = name
let shopPathSnap = withSnap.childSnapshot(forPath: "ShopPath")
let shopChildSnap = shopPathSnap.children.allObjects as! [DataSnapshot]
for childDataSnap in shopChildSnap { //iterate over the array in ShopPath
let height = childDataSnap.childSnapshot(forPath: "Height").value as! String
print(" height: \(height)")
self.height = height
}
}
}
And the output looks like this
Shop name: Test
height: 1,180
Shop name: Test 2
height: 2,000
I left off the other child nodes as if you can read height, you can read the rest. So this just assigns and prints out the shop name and height (as a string).
A suggestion as well. Arrays are not well suited for NoSql databases and their use is very situational (avoid if possible). If you're using an array, there's probably a better structure available.