swift firebase一对多示例？

我已经创建了以下两个表。我想选择tablefriends，我想显示table user中的姓名？任何人都可以帮助我，例如在swift请谢谢你

表用户

 id
 name
 email

餐桌朋友

 id
 user_id
 friend_id

---

您的实时数据库应该是这样的

{
    "users": {
        "1": {
            "name": "John Doe",
            "email": "john@example.com"
        },
        "2": {
            "name": "Jane Doe",
            "email": "jane@example.com"
        }
    },
    "user-friends": {
        "1": {
            "2": true
        },
        "2": {
            "1": true
        }
    }
}

为了获得John的朋友，我们观察路径

/user friends/1

let uid = 1 // the uid of the user we want the friends of
let ref = FIRDatabase.database().reference().child('user-friends/\(uid)')

ref.observeEventType(.ChildAdded, block: { snapshot in

    let uid = snapshot.key // the uid of a user who is John's friend
    let ref = FIRDatabase.database().reference().child('users/\(uid)')

    ref.observeSingleEventOfType(.Value, block: { snapshot in
        if let json = snapshot.value as? [String:AnyObject] {
            print(json["name"])
        }
    })
})

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