使用Firebase和Swift从未知的子名称中检索数据 [英] Retrieve data from an unknown child name with Firebase and Swift

问题描述

我将Firebase用作IOS应用程序的数据库.我想从数据库中检索几个用户的数据.

I'm using Firebase as the database for my IOS app. I want to retrieve data of several users from the database.

这是我的数据库组织:

• 用户

• UserID1
  • 位置:value1
  • 位置:Value2

  ...

  我想检索数据库所有用户的位置数据.

  I want to retrieve the location data of all the users of the database.

  基本快照功能

      ref.child("Users").child("").child("Location").observe(.value, with: {
          snapshot in
  
          for Location in snapshot.children {
              self.locationsArray.append((Location as AnyObject).key)
          }
          print(self.locationsArray)
      })
  

  我的问题是:即使我未指定(我无法指定)作为孩子名字的userID，如何获取所有 Locations 前?谢谢.

  My question is: how can I retrieve all the Locations even if I don't specify (I can't) the userID that is the name of a child before? Thanks.

  推荐答案

  下面是一个代码段，该代码段检索并打印每个用户的uid及其位置.

  Here's a code snippet that retrieves and prints the uid of each user and their location.

  我们可以使用.query进一步完善结果

  We can further refine our results with a .query

  let usersRef = ref.child("users")
  usersRef.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] //child data
          let location = userDict["Location"] as! String
          print("key = \(uid) is at location = \(location)")
      } 
  })
  

  这篇关于使用Firebase和Swift从未知的子名称中检索数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！