如何通过键值从Firebase中检索对象 [英] How to retrieve objects from firebase by key value

问题描述

我是firebase的新手，并且拥有我的firebase项目的结构

我想获得所有的对象，即感兴趣的值等于men我写了这样的代码，得到所有按照interes排序的对象：

  let thisUserRef = URL_BASE.childByAppendingPath（profile）
 
 thisUserRef.queryOrderedByChild（Interest）
 .observeEventType（.Value，withBlock：{snapshot in 
 
如果让UserInterest = snapshot.value！[Interest] as？String {
 print（snapshot.key）
} 
} 
  

但是我收到nil。

解决方案

您需要遍历所有键值配置文件

 如果让allProfiles = snapshot.v alue as？[String：AnyObject] {
 for（_，profile）in allProfiles {
 print（profile）; 
 let userInterest = profile [Interest] 
} 
} 
  

这里_是格式为 KYXA-随机字符串的关键字，配置文件将是该键的元素。

编辑：

根据 docs 。
$ b 尝试 thisUserRef。 queryOrderedByChild（Interest）。equalTo（men）然后使用我在回答中指定的内部循环

I'm new to firebase and I have such structure of my firebase project

I want to get all objects, that "Interested" value is equal to "men"

I wrote such code, to get all object sorted by interes value:

let thisUserRef = URL_BASE.childByAppendingPath("profile")

thisUserRef.queryOrderedByChild("Interest")
     .observeEventType(.Value, withBlock: { snapshot in

     if let UserInterest = snapshot.value!["Interest"] as? String {    
          print (snapshot.key)  
     }
}

But I receive nil.

解决方案

you need to loop through all the key-value profiles

      if let allProfiles = snapshot.value as? [String:AnyObject] {
            for (_,profile) in allProfiles {
                  print(profile);
                  let userInterest = profile["Interest"]
           }
       }

Here _ is the key that is in the format KYXA-random string and profile will be the element for that key.

Edit:

There is querying for child values as per the docs.

Try thisUserRef.queryOrderedByChild("Interest").equalTo("men") and then using the inner loop that i specified in the answer

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