Firebase数据库不等于请求 - 替代解决方案（适用于iOS）

问题描述

  {
post-评论：{
post-id-1：{
comment-id-11：{
author：user1，
text： Hello world，
uid：user-id-2
}，.... 
} 
  

我想拉取所有的评论，但不包括当前用户的一个。

在SQL中，这将被翻译进入：
从后注释中选择*其中id！=user-id-2

据我所知，Firebase数据库不提供排除方法节点基于值的存在（即：用户ID！= ...）。

因此，是否有其他解决方案来解决这个问题。可以通过更改数据库结构，也可以在数据加载完成后处理数据源。

对于后者，我使用的是FirebaseTableViewDataSource。是否有一种方法来过滤查询后的数据？

非常感谢

解决方案第一种解决方案是通过.ChildAdded加载注释并忽略当前user_id的注释

$ $ p $ let commentsRef = self.myRootRef.childByAppendingPath（comments）

commentsRef.observeEventType（.ChildAdded，withBlock：{snapshot in

let uid = snapshot.value [uid] as！String
if uid！= current_uid {
// do stuff
}
}）


你可以在这里进行扩展，并通过.Value载入所有内容，并在代码中遍历子元素。该方法将取决于您正在加载多少个节点.ChildAdded将会降低内存使用量。

I am using Firebase database with a Json structure to manage users' comments.

 {
    "post-comments" : {
            "post-id-1" : {
              "comment-id-11" : {
                "author" : "user1",
                "text" : "Hello world",
                "uid" : "user-id-2"
              },....
 }

I would like to pull all the comments but excluding the current user's one.

In SQL this will be translated into:Select * from post-comments where id !="user-id-2"

I understand that Firebase database does not offer a way to excludes nodes based on the presence of a value (ie: user id != ...).

Thus is there any alternative solutions to tackle this. Either by changing the Database structure, of maybe by processing the datasource once the data are loaded.

For the latter I am using a FirebaseTableViewDataSource. is there a way to filter the data after the query?

Thanks a lot

解决方案

The first solution is to load the comments via .ChildAdded and ignore the ones with the current user_id

let commentsRef = self.myRootRef.childByAppendingPath("comments")

commentsRef.observeEventType(.ChildAdded, withBlock: { snapshot in

  let uid = snapshot.value["uid"] as! String
  if uid != current_uid {
    //do stuff
  }
})

You could expand on this and load everything by .Value and iterate over the children in code as well. That method will depend on how many nodes you are loading - .ChildAdded will be lower memory usage.

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