当您不知道文档索引时,在mongodb数组中更新嵌套记录 [英] Updating a nested record in mongodb array when you don't know the document index
问题描述
我想更新嵌套文档的记录,我的文档如下所示:
I want to update the record of a nested document, my document looks like this:
[
{
"_id": "60753fd9b249ad0dfa1eeb48",
"name": "Random Name 1",
"email": "randomname1@zmel.kom",
"likings": [
{
"breakfast": {
"eat": "oats",
"drink": "milk"
}
},
{
"lunch": {
"eat": "beef",
"drink": "pepsi"
}
},
{
"dinner": {
"eat": "steak",
"drink": "champagne"
}
}
]
},
{
"_id": "60753fd9b249ad0dfa1eeb58",
"name": "Random Name 2",
"email": "randomname2@zmel.kom",
"likings": [
{
"breakfast": {
"eat": "cereals",
"drink": "coffee"
}
},
{
"lunch": {
"eat": "salad",
"drink": "hot-water"
}
},
{
"dinner": {
"eat": "biryani",
"drink": "apple juice"
}
}
]
}
]
现在,我想为 Random Name 2
的 dinner
修改 drink
的值,但是我不知道晚餐的索引,它可以在午餐
之上,也可以在早餐
之下.
这是我在Python中尝试过的内容:
Now I want to update the value of drink
for dinner
for Random Name 2
but I don't know the index of dinner, it could be above the lunch
, it could be just below the breakfast
.
Here's what I have tried in Python :
oid = data[0] # fetched from flask form
to_be_updated = data[1] # fetched from flask form
update_value = data[2] # fetched from flask form
condition = {"_id" : oid}
update_value = {
"$set" : {
f"likings.{to_be_updated}.drink" : update_value
}
}
response = mongo.db.food.update(condition, update_value)
但我遇到的错误是: pymongo.errors.WriteError:无法在元素<完整元素描述>
中创建字段晚餐"我计划使用的其他策略是,只匹配ID,然后通过保留不需要更改的值并更改我要更改的值来更新 likings
.但是这种方法似乎太明显了,从语义上来说是错误的,因为我使用的不是更新而是更新这种策略,即没有任何实际原因干扰收集模式.有没有办法做到这一点,还是我应该继续我的想法
but the error I am getting is:
pymongo.errors.WriteError: Cannot create field 'dinner' in element <complete element description>
What my other strategy that I am planning on using is, only match ID and then update likings
by keeping the values that are no needed to be changed as it is and altering that value that i want to change. But this approach seems too obvious and semantically wrong since I am using not updating but updating
kind of strategy i.e disturbing the collection schema for no actual reason. Is there a way to do that or should I just continue with what I am thinking
推荐答案
演示:MongoDB游乐场
首先,您的JSON中有错误.
First of all, there are errors in your JSON.
[
{
"_id": "60753fd9b249ad0dfa1eeb48",
"name": "Random Name 1",
"email": "randomname1@zmel.kom",
"likings": [
{
"breakfast": {
"eat": "oats",
"drink": "milk"
}
},
{
"lunch": {
"eat": "beef",
"drink": "pepsi"
}
},
{
"dinner": {
"eat": "steak",
"drink": "champagne"
}
}
]
},
{
"_id": "60753fd9b249ad0dfa1eeb58",
"name": "Random Name 2",
"email": "randomname2@zmel.kom",
"likings": [
{
"breakfast": {
"eat": "cereals",
"drink": "coffee"
}
},
{
"lunch": {
"eat": "salad",
"drink": "hot-water"
}
},
{
"dinner": {
"eat": "biryani",
"drink": "apple juice"
}
}
]
}
]
尝试一下:
db.collection.update({
"name": "Random Name 2",
"likings.dinner": {
"$exists": true
}
},
{
"$set": {
"likings.$.dinner.drink": "PEPSI"
}
})
您可以将晚餐
更改为要相应更新的任何字段.
You can change dinner
to whatever field you want to update accordingly.
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