Swift 3 and Firebase: Retrieve Auto Id Value from Snapshot

Swift 3 and Firebase: Retrieve auto id value from snapshot

.value returns the parent node and all of the child nodes that satisfy the results of the query. In this case, the children would need to be iterated over (there could be more than 1 child that matches the query).

The snapshot.key is the parent node key (bS6JPkEDXIVrlYtSeQQgOjCNTii1) and the value is a snapshot (dictionary) of all of the children. Each of those children is a key:value pair of uid:value and value a dictionary of the child nodes, receiverId, senderId etc

This code will print the uid of each child node and one of the values, timestamp, for each user node that matches the query.

    let usersRef = ref.child("users")
    let queryRef = usersRef.queryOrdered(byChild: "receiverId")
                           .queryEqual(toValue: "LKupL7KYiedpr6uEizdCapezJ6i2")

    queryRef.observeSingleEvent(of: .value, with: { (snapshot) in

        for snap in snapshot.children {
            let userSnap = snap as! FIRDataSnapshot
            let uid = userSnap.key //the uid of each user
            let userDict = userSnap.value as! [String:AnyObject]
            let timestamp = userDict["timestamp"] as! String
            print("key = \(uid) and timestamp = \(timestamp)")
        } 
    })

How to get value from autoID in Firebase Database - Swift

The easiest way to get the count of guests who are marked as attending is to use a query:

let ref = Database.database().reference().child("userInfo").child(uid!)
let query = ref.child("guests").queryOrdered(byChild: "attending").queryEqual(toValue: "attending")
query.observe(.value) { snapshot in
    let numberOfusers = snapshot.childrenCount
    print(snapshot.childrenCount)
}

How to Firebase retrieve data below UID and auto ID In Swift

Right now your code is looping over the child nodes of /Users/Sellers, which is the nodes of each individual user. What you seem to want to do is include all nodes under the product_list property of each user, which requires an extra nested loop:

let refList = Database.database().reference().child("Users/Sellers")

refList.observe(DataEventType.value, with:{(snapshot) in
    if snapshot.childrenCount>0{
        self.listProduct.removeAll()

        for user in snapshot.children.allObjects as! [DataSnapshot]{
            let productList = user.childSnapshot(forPath: "product_list")
            for product in productList.children.allObjects as! [DataSnapshot]{
              let userList = product.value as? [String: AnyObject]
              let listName = userList?["name"]
              let listDetail = userList?["details"] // NOTE: also fixed a typo here
              let listPrice = userList?["price"]
              print("key = \(listName)")

              let list = ListModel(name: listName as! String?, detail: listDetail as! String?, price: listPrice as! String?)

              self.listProduct.append(list)

            }
        }
        self.tableList.reloadData()
    }

})

retrieving data from auto id database child

Since you have childByAutoId you have to use query ordered and query equal.

let reference = Database.database().reference().child("User_Informations").queryOrdered(byChild: "email")
reference.queryEqual(toValue: "ali_y_k@hotmail.com").observeSingleEvent(of: .childAdded) { (snapshot) in
     let dictionary = snapshot.value as! [String : Any]
     let firstName = dictionary["firstName"]
     print(firstName)
}

Reading Data stored via Autoid from Firebase Swift

The way I usually do this is by:

ref.child("Phrases").observeSingleEvent(of: .value, with: { snapshot in

 let value = snapshot.value as! [String:Any]
 let name = value["phrase"] as? String ?? ""
})

Alternatively you could unwrap it first

ref.child("Phrases").observeSingleEvent(of: .value, with: { snapshot in

  if let value = snapshot.value as? [String:Any] {
    let name = value["phrase"] as? String ?? ""
  }
})

Get information from Firebase Database without autoID

I think the confusion stems from the fact that you are observing .childAdded. Since you're only observing one node/entity, you'll want to observe .value instead:

Database.database().reference()
    .child("users/BA917746-F5BE-4FA4-B23E-C998F4118CCE")
    .observe(.value) { (snapshot) in
          
        let dict = snapshot.value as! [String: Any]
                        
        self.name = dict["name"] as! String

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If you we're to observe the entire users node, that's when you'd either use .childAdded or loop over the child nodes of the snapshot.

How can I retrieve data with queryEqualToValue in auto id child. Firebase-iOS

Given your realtime database looks something like this:

{
    "students": {
        1: {
            "name": {
                "first_name": "Nathapong",
                "nick_name": "Oniikal3"
            }
        }
    }
}

You can observe the students path with the event type ChildAdded and order the query by child key name/first_name. Then you can use queryEqualToValue to find students with a particular first name.

let ref = FIRDatabase.database().referenceWithPath('students').queryOrderByChild("name/first_name").queryEqualToValue("Nathapong")

ref.observeSingleEventOfType(.ChildAdded, block: { snapshot in
    print(snapshot)
})

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