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How to retrieve nested nodes from Firebase realtime database to iOS app

I'm building a simple app which stores and retrieve data from firebase realtime database. At present my database has these data of an user. Database content

Here is the code which I used to insert data.

 let ref = Database.database().reference()
    let user = ref.child("bill")
    user.setValue(["name":"Bill gates"])
    user.child("Request/One").setValue(["Phno":" ","Message":" "])

As you can see I'm inserting a dictionary with empty values because I don't know how to create a child node without any data within them.

I'm trying to retrieve the Request part of the database completely whenever a new node is added as a child to request node.

Here I my code for retrieving

   user.observe(.childAdded) { (DataSnapshot) in
        
        for case let  i as DataSnapshot in DataSnapshot.children
        {
            guard let dict = i.value as? [String:Any] else{print("Error"); return}
            let a = dict["Message"] as? String
            let b = dict["Phno"] as? String
            print(a!)
            print(b!)
        }
    }

But in above code it doesn't get called when I explicitly add a new node in database

Solved it by using below code

user.observe(.childAdded) { (DataSnapshot) in
   
   if let dict = DataSnapshot.value as? NSDictionary
   {
    for i in dict.allKeys
    {
        if let data = dict[i] as? NSDictionary
        {
            let message = data["Message"] as! String
            let phno = data["Phno"] as! String
            
            if(message != "" && phno != "")
            {
                print(message)
                print(phno)
            }
        
    }
   }
    
}

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