queryOrderBy中的Firebase访问键 [英] Firebase access keys in queryOrderBy
问题描述
我有两个与此查询相关的问题：
-
我在Firebase中执行查询，查询返回结果我正在寻找，但当我试图访问查询中的数据，它是零
-
如何访问查询中的标签密钥？这是1深
预先感谢您
Query
ref.child（users）
.queryOrderedByChild（receivePostRequest / status）
.queryEqualToValue（true）
.observeEventType（.Value，withBlock：{snapshot in
JSON结果
可选（{
lgmSZ1HnMnSzE71kCLfdxK8AN2G2 = {
age = 18;
email =
firstname = Jamie;
lastname = lon;
latitude =37.3325232;
longitude =-122.0286527;
profilePic = users / profilePhoto / W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg;
receivePostRequest = {
status = 1; $ b $ tag = tagSample;
$ b $;}
userId = lgmSZ1HnMnSzE71kCLfdxK8AN2G2 ;
};
}）
这是完整的查询
ref.child（ $ users）
.queryOrderedByChild（receivePostRequest / status）
.queryEqualToValue（true）
.observeEventType（.Value，withBlock：{snapshot in
print（snapshot.value [firstname]）
}）
JSON
{
posts：{
-KJGom2RvmWkfbvsFXij：{
postAddress：Post Address，
postCompletionAddress：post completion address，
postCreationTime：postCreation Time，
postDateTime：日期和时间，
postDescription：详细信息，
postPay：post pay，
postTitle：Post Title，
status：pending，
userAiD： W6pK2HHA1TZC9wicnCaODQhHvoi1，
userBiD：lgmSZ1HnMnSzE71kCLfdxK8AN2G2
}，
}，
users：{
W6pK2HHA1TZC9wicnCaODQhHvoi1：{
age ：18，
email：ama@gmail.com，
firstname：jam，
lastname：lime，
latitude：37.332172，
longitude：-122.035089，
profilePic：users / profilePhoto / W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg，
receivePostRequest：{
lat：28.10277584477151，
latitude：37.33067237，
long：-81.4587166999294，
longitudinal：-122.03014382，
status：false，
tags：{
tag1：444
}
}，
userId：W6pK2HHA1TZC9wicnCaODQhHvoi1
$ blgmSZ1HnMnSzE71kCLfdxK8AN2G2：{
age：18，
email：weirhe@gmail.com，
firstname：james ，
lastname：leen，
latitude：37.3325232，
longitude：-122.0286527，
profilePic：users / profilePhoto / W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg ，
receivePostRequest：{
status：true，
tag：tag 1
}，
userId：lgmSZ1HnMnSzE71kCLfdxK8AN2G2
}
}
}
如果Firebase中存储的整数值为1
node_0
测试：1
node_1
测试：true
node_2
test：1
如果查询是
queryOrderedByChild（test）。queryEqualToValue（true）
<只有node_1会被返回，因为它是真的。同样，
pre $> queryOrderedByChild（test）。queryEqualToValue（1）
只有node_0和node_2会返回是$ 1
并回答这个问题：
$ p $print（snapshot .value）//打印节点中的所有数据
当您返回.Value时，快照wi所以有一个方法来访问每个孩子的钥匙是：
在snapshot.children中的孩子{
让key = child.key作为字符串
print（key）
}
这个会打印每个父节点的键值，lgmSZ1HnMnSzE71kCLfdxK8AN2G2在这种情况下
为了回应评论/问题
但是我也试着检索
tag：tag 1
从child = snapshot.children循环中找不到最初明显的方法，所以以下是如何操作的方法
为snapshot.children中的子元素{
let receivePostRef = child.childSnapshotForPath（receivePostRequest）
让aTag = receivePostRef.value [tag]
print（setting = \（aTag））// print's Tag1
}
I have 2 questions relating to this query:
I'm running a query in Firebase, the query returns the result I'm looking for but when I try to access the data in the query, it is nil
How can I access the tag key in the query? It is 1 deep
Thank you in advance
Query
ref.child("users") .queryOrderedByChild("receivePostRequest/status") .queryEqualToValue(true) .observeEventType(.Value, withBlock: {snapshot inJSON result
Optional({ lgmSZ1HnMnSzE71kCLfdxK8AN2G2 = { age = 18; email = "lon1@gmail.com"; firstname = Jamie; lastname = lon; latitude = "37.3325232"; longitude = "-122.0286527"; profilePic = "users/profilePhoto/W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg"; receivePostRequest = { status = 1; tag = tagSample; }; userId = lgmSZ1HnMnSzE71kCLfdxK8AN2G2; }; })This is the complete query
ref.child("users") .queryOrderedByChild("receivePostRequest/status") .queryEqualToValue(true) .observeEventType(.Value, withBlock: {snapshot in print(snapshot.value["firstname"]) })JSON
{ "posts" : { "-KJGom2RvmWkfbvsFXij" : { "postAddress" : "Post Address", "postCompletionAddress" : "post completion address", "postCreationTime" : "postCreation Time", "postDateTime" : "Date and Time", "postDescription" : "Post Detail", "postPay" : "post Pay", "postTitle" : "Post Title", "status" : "pending", "userAiD" : "W6pK2HHA1TZC9wicnCaODQhHvoi1", "userBiD" : "lgmSZ1HnMnSzE71kCLfdxK8AN2G2" }, }, "users" : { "W6pK2HHA1TZC9wicnCaODQhHvoi1" : { "age" : 18, "email" : "ama@gmail.com", "firstname" : "jam", "lastname" : "lime", "latitude" : 37.332172, "longitude" : -122.035089, "profilePic" : "users/profilePhoto/W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg", "receivePostRequest" : { "lat" : 28.10277584477151, "latitude" : 37.33067237, "long" : -81.4587166999294, "longitud" : -122.03014382, "status" : false, "tags" : { "tag1" : 444 } }, "userId" : "W6pK2HHA1TZC9wicnCaODQhHvoi1" }, "lgmSZ1HnMnSzE71kCLfdxK8AN2G2" : { "age" : 18, "email" : "weirhe@gmail.com", "firstname" : "james", "lastname" : "leen", "latitude" : 37.3325232, "longitude" : -122.0286527, "profilePic" : "users/profilePhoto/W6pK2HHA1TZC9wicnCaODQhHvoi1.jpg", "receivePostRequest" : { "status" : true, "tag" : "tag 1" }, "userId" : "lgmSZ1HnMnSzE71kCLfdxK8AN2G2" } } }解决方案Careful with the 1 and true as they will return different results
If you have an integer value of 1 stored in Firebase
node_0 test: 1 node_1 test: true node_2 test: 1if the query is
queryOrderedByChild("test").queryEqualToValue(true)only node_1 will be returned, as it's true
Likewise
queryOrderedByChild("test").queryEqualToValue(1)only node_0 and node_2 will be returned as they are 1
And to answer the question:
print(snapshot.value) //prints all of the data in the nodeand when you are returning .Value, the snapshot will have children so one way to access the keys of each child is:
for child in snapshot.children { let key = child.key as String print(key) }this will print each parent node key, lgmSZ1HnMnSzE71kCLfdxK8AN2G2 in this case
Edit
In response to the comment/question
but im also trying retrieve
"tag" : "tag 1There is not an initially obvious way to get to that from a child = snapshot.children loop, so here's how you do it
for child in snapshot.children { let receivePostRef = child.childSnapshotForPath("receivePostRequest") let aTag = receivePostRef.value["tag"] print("setting = \(aTag)") //print's Tag1 }这篇关于queryOrderBy中的Firebase访问键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！
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