I'm having trouble with my mongoDB (v3.6.4), below is what my data looks like right now. I need to find (and update) the "text" value for a certain element in "second_list", i.e. return "hello" and change it to "hello world " in next step.
{
"_id": ObjectId("xxxxxxxxxxxxx"),
"top_list": [
{
"create_time": "2019-06-10 15:56:46",
"second_list": [
{
"name": "v1",
"text": "hello"
},
{
"name": "v2",
"text": "good morning"
},
{
"name": "v3",
"text": "bye"
}
]
}
]
}
i have tried this query
db.myCollection.find(
{'top_list.second_list.name':'v1'},
{"top_list.second_list":1,"_id":0}
)
but it returned the whole of "second_list". What i want should be
{
"name": "v1",
"text": "hello"
}
or just the string "hello".
This syntax works for me to find and update a value
db['myCollection'].findAndModify({query:{_id: ObjectId("xxxxxxxxxxxxx")}, update: {$set: {"top_list.second_list.0.text":"someNewText"}}})
The 0 in top_list.second_list.0.text is the array index you're wanting to access
Mongodb Has function Called FindAndModify
and your query should be like this
and the $ array operators in this link will help to modify what you want
Like $elemmatch
Related
I have following document structure stored in Mongodb. Please note "next" is an array.
{
"id": 1,
"pricing": [
{
"name": "name1",
"value": "v1",
"next": [
{
"name": "name2",
"value": "v2",
"next": [
{
"name": "name3",
"value": "v3",
"next": [
]
}
]
}
]
}
]
}
How can I find the eg. name=name3 or any arbitrary value from it? Not knowing if it exists or not.
You can match the field pricing.next.next.name and the value name3 like this.
db.collection.find({
"pricing.next.next.name": "name3"
})
So it will return the document that contains the value name3 inside the two arrays.
Mongo Playground example here
Your question is not explained too well, so, maybe you mean, how to get only the field name after querying by name. Note that you can use other field like value to query the document.
Then, you have to do this:
db.collection.find({
"pricing.next.next.name": "name3",
},
{
"pricing.next.next.name": 1
})
And mongo Playground example here
I have a collection with documents like:
{
"_id": "Mongo ObjectID",
"some_prop": "some_value",
"features": [
{ "name": "A", "icon": "01.png" },
{ "name": "B", "icon": "02.png" }
]
}
Another document sample:
{
"_id": "Mongo ObjectID",
"some_prop": "other one",
"features": [
{ "name": "B", "icon": "02.png" },
{ "name": "C", "icon": "03.png" },
{ "name": "D", "icon": "04.png" }
]
}
Notice that in the first document and the second there is the same feature B. This occurs all over many documents.
What I need is to update all features B to a new icon, something like this:
{ "name": "B", "icon": "10.png" }
I need to apply this change for all documents that has a feature with name B.
I already did a very horrible code to get all documents and update one by one in a loop. But my guess is there is a better way to do it, maybe in a single collection.update command? I'm new in MongoDB and so far googling didnt work.
You need to use $positional operator to update the fields inside an array
db.collection.updateMany(
{ "features.name": "B" },
{ "$set": { "features.$.icon": "10.png" }}
)
Not sure I am using the right terminology here, but assume following oversimplified JSON structure available in Mongo :
{
"_id": 1234,
"labels": {
"label1": {
"id": "l1",
"value": "abc"
},
"label3": {
"id": "l2",
"value": "def"
},
"label5": {
"id": "l3",
"value": "ghi"
},
"label9": {
"id": "l4",
"value": "xyz"
}
}
}
{
"_id": 5678,
"labels": {
"label1": {
"id": "l1",
"value": "hjk"
},
"label5": {
"id": "l5",
"value": "def"
},
"label10": {
"id": "l10",
"value": "ghi"
},
"label24": {
"id": "l24",
"value": "xyz"
}
}
}
I know my base element name (labels in the example), but I do not know the various sub elements I can have (so in this case the labelx names).
How can I group / count the existing elements (like as if I would be using a wildcard) so I would get some distinct overview like
"label1":2
"label3":1
"label5":2
"label9":1
"label10":1
"label24":1
as a result? So far I only found examples where you actually need to know the element names. But I don't know them and want to find some way to get all possible sub element names for a given top element for easy review.
In reality the label names can be pretty wild, I used labelx for readability in the example.
You can try below aggregation in 3.4.
Use $objectToArray to transform object to array of key value pairs followed by $unwind and $group on key to count occurrences.
db.col.aggregate([
{"$project":{"labels":{"$objectToArray":"$labels"}}},
{"$unwind":"$labels"},
{"$group":{"_id":"$labels.k","count":{"$sum":1}}}
])
I have some mongodb documents which structure like:
{
"_id": ObjectId("58c212b06ca3472b902f9fdb"),
"Auction name": "Building",
"Estimated price": "23,660,000",
"Auction result": "success",
"Url": "https://someurl.htm",
"match_id": "someid",
"Final price": "17,750,000",
"Area": [
{
"Area": "696.77"
}
]
}
The "match_id" is used for update query and after that I don't need this entry anymore.
Is there any idea to drop this entry and keep the rest of the document?
Have you tried simpily using an update query to unset the field like the following
db.products.update(
{},
{ $unset: { match_id: "" } }
)
Keep in mind that the first set of curly braces has been intentionally left blank so that your update query matches every entry in your collection
I have document like below in MongoDB:
{
"_id": "test",
"tasks": [
{
"Name": "Task1",
"Parameter": [
{
"Name": "para1",
"Type": "String",
"Value": "*****"
},
{
"Name": "para2",
"Type": "String",
"Value": "*****"
}
]
},
{
"Name": "Task2",
"Parameter": [
{
"Name": "para1",
"Type": "String",
"Value": "*****"
},
{
"Name": "para2",
"Type": "String",
"Value": "*****"
}
]
}
]
}
There is Embedded Data Structure (Parameter) inside of another Embedded Data Structure (Tasks). Now I want to update the para1 in Task1's Parameter.
I have tried many ways but I can only use query tasks.Parameter.name to find the para1 but cannot update it. the example in the doc are using .$. to update the value in a Embedded Data Structure but it doesn't work in my case.
Anyone have any ideas ?
MongoDB currently only supports the positional operator once, and only for the top level array. There is a ticket SERVER-831 to change this behavior for your use case. You can follow the issue there and up vote it.
However, you might be able to change your approach to accomplish what you want to do. One way is to change your schema. Collapse the tasks name into the array so the document looks like this:
{
_id:test,
tasks:
[
{
Task:1
Name:para1,
Type:String,
Value:*****
},
{
Task:1
Name:para2,
Type:String,
Value:*****
},
{
Task:2
Name:para1,
Type:String,
Value:*****
},
{
Task:2
Name:para2,
Type:String,
Value:*****
}
]
}
Another approach that may work for you is to use $pull and $push. For instance something like this to replace a task (this assumes that tasks.Parameter.Name is unique to an array of Parameters):
db.test2.update({$and: [{"tasks.Name": "Task3"}, {"tasks.Parameter.Name":"para1"}]}, {$pull: {"tasks.$.Parameter": {"Name": "para1"}}})
db.test2.update({"tasks.Name": "Task3"}, {$push: {"tasks.$.Parameter": {"Name": "para3", Type: "String", Value: 1}}})
With this solution you need to be careful with regard to concurrency, as there will be a brief moment where the document doesn't exist.