Fetch all children from database

问题

In my app is tableview where i want to show all child of my customers. This is database structure:

When previously under Customers I had only one child then I knew how to show customers when path was usersDatabase/userID/Customers. But in this moment my path is usersDatabase/userID/Customers/userSpecificName and my tableview show blank cell. What I must add in my code to properly working of code?

This is code when I import data from Database:

let userID = Auth.auth().currentUser!.uid
    ref = Database.database().reference().child("usersDatabase").child(userID).child("Customers")

    ref.observe(DataEventType.value, with: { (snapshot) in
        if snapshot.childrenCount > 0 {
            self.services.removeAll()
            self.filteredServices.removeAll()
            for results in snapshot.children.allObjects as! [DataSnapshot] {
                let results = results.value as? [String: AnyObject]
                let name = results?["Name and surname"]
                let phone = results?["Phone"]
                let customerID = results?["ID"]

                let myCustomer = CustomerModel(name: name as? String, phone: phone as? String, customerID: customerID as? String)
                self.services.append(myCustomer)
                self.filteredServices.append(myCustomer)
            }
            self.tableView.reloadData()
        }
    })

What I should add to line ref = Database.database().reference().child("usersDatabase").child(userID).child("Customers") that tableview show child of added Customers (Ben Smith and Tom Cruise)?

回答1:

This answer is similar to a prior answer here

What you want to do is to treat each child in Customers as a DataSnapshot, then the children can be accessed.

Given a Firebase structure:

usersDatabase
  uid_0
     Customers
        Ben Smith
           data: "Some data"
        Tom Cruise
           data: "Some data"
  uid_1
     Customers
        Leroy Jenkins
           data: "Some data"
  uid_2
     Customers
        De Kelly
           data: "Some data"
     etc

The code to print out each user and their customers is

let usersDatabaseRef = Database.database().reference().child("usersDatabase")
usersDatabaseRef.observe(.value, with: { snapshot in
    print("there are \(snapshot.childrenCount) users")
    for child in snapshot.children {
        let childSnap = child as! DataSnapshot
        print("user: \(childSnap.key)")
        let userCustomerSnap = childSnap.childSnapshot(forPath: "Customers")
        for customer in userCustomerSnap.children {
            let customerSnap = customer as! DataSnapshot
            print(" customer: \(customerSnap.key)")
        }
    }
})

and the output

there are 3 users
user: uid_0
 customer: Ben Smith
 customer: Tom Cruise
user: uid_1
 customer: Leroy Jenkins
user: uid_2
 customer: De Kelly
 customer: Leonard Nimoy
 customer: William Shatner

Edit: the OP wanted to know how to get to the data node under each customer so here's a slightly modified version with output

let usersDatabaseRef = Database.database().reference().child("usersDatabase")
usersDatabaseRef.observe(.value, with: { snapshot in
    print("there are \(snapshot.childrenCount) users")
    for child in snapshot.children {
        let childSnap = child as! DataSnapshot
        print("user: \(childSnap.key)")
        let userCustomerSnap = childSnap.childSnapshot(forPath: "Customers")
        for customer in userCustomerSnap.children {
            let customerSnap = customer as! DataSnapshot
            let dict = customerSnap.value as! [String: Any]
            let value = dict["data"] as! String

            print(" customer: \(customerSnap.key)")
            print("    and their data is: \(value)")
        }
    }
})

and the output

there are 3 users
user: uid_0
 customer: Ben Smith
    and their data is: some data
 customer: Tom Cruise
    and their data is: some data
user: uid_1
 customer: Leroy Jenkins
    and their data is: some data
user: uid_2
 customer: De Kelly
    and their data is: some data
 customer: Leonard Nimoy
    and their data is: some data
 customer: William Shatner
    and their data is: some data

来源：https://stackoverflow.com/questions/50383693/fetch-all-children-from-database