Learning MongoDB so I hope that this is not a duplicate question.
So big picture. Users can add/remove items from their cart (which is an array).
The cart array holds objects who are structured as follows: {_id: 123r32, qty: 2}
The user document is structured as follows:
_id: 123432423,
username: johndoe,
email: johndoe#mail.com,
cart: [
{
_id: wefw3423,
qty: 100
}
]
So adding to the array is fine:
db.users.updateOne({_id: req.user.id}, {$push: {cart: {_id: req.body.id, qty: req.body.qty}}})
But when I push, I don't want to add a duplicate. I want to just adjust the qty (add/subtract) accordingly. If no instance of that _id exists, push.
Thank you for reading and your help! Should you need additional information, please ask I shall provide!.
EDIT:
Additional information. The request body (req.body) will contain only ONE item. So updateMany will not be required here.
db.users.updateOne({_id: req.user.id}, {$set: { "cart.$[element]": {_id:"wefw3423",qty:50}}, { arrayFilters: [ { element: _id:"wefw3423" } ]},{ upsert:true})
MongoDB reference :
https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/#mongodb-update-up.---identifier--
Related
I've been scratching my head with this problem. I've attempted to search for a solution but I didn't find anything relating to my specific use case.
Would anyone be able to help me out?
Say I have a collection of "discount" documents, and importantly they have an "amount" field to say how much the discount is worth. Whenever a discount is redeemed I currently want to track what the worth was at the time of the redemption.
To do this I've been attempting to use the following code:
await datastore.collection('discounts').updateOne(
{
$expr: { $gt: [ '$maxUses', '$uses' ] },
...criteria
},
{
$set: {
uses: 1
},
$push: {
redemptions: {
name: concatNames(user),
email: user.email,
amount: '$amount', // <-- use amount from root document
when: new Date()
}
}
}
)
Unfortunately $amount does not pull the value from the root document, instead it just becomes "$amount" as a string. I've also attempted to convert this update to use a pipeline but $push is not a valid pipeline stage.
Here's a quick Mongo playground link.
Thanks in advance.
In order to refer to another fields value, you'll need to use the aggregation pipeline form of update. However, '$push' is an update operator, not an aggregation operator.
$concatArrays gets most of the way there like
{$set: {redepmtions: {$concatArrays: [ "$redemptions", [{amount: "$amount"}]}}
That will throw an error if $redemptions doesn't already exist, so use $cond to subsitute an empty array in that case:
.updateOne(
{ ...criteria },
[{$set: {
redemptions: {$concatArrays: [
{$cond: [{$eq: ["array", {$type: "$redemptions"}]}, "$redemptions", []]},
[{amount: "$amount"}]
]}
}}]
)
Playground
I have a schema which has one field named ownerId and a field which is an array named participantIds. In the frontend users can select participants. I'm using these ids to filter documents by querying the participantIds with the $all operator and the list of participantsIds from the frontend. This is perfect except that the participantsIds in the document don't include the ownerId. I thought about using aggregate to add a new field which consists of a list like this one: [participantIds, ownerId] and then querying against this new field with $all and after that delete the field again since it isn't need in the frontend.
How would such a query look like or is there any better way to achieve this behavior? I'm really lost right now since I'm trying to implement this with mongo_dart for the last 3 hours.
This is how the schema looks like:
{
_id: ObjectId(),
title: 'Title of the Event',
startDate: '2020-09-09T00:00:00.000',
endDate: '2020-09-09T00:00:00.000',
startHour: 1,
durationHours: 1,
ownerId: '5f57ff55202b0e00065fbd10',
participantsIds: ['5f57ff55202b0e00065fbd14', '5f57ff55202b0e00065fbd15', '5f57ff55202b0e00065fbd13'],
classesIds: [],
categoriesIds: [],
roomsIds: [],
creationTime: '2020-09-10T16:42:14.966',
description: 'Some Desc'
}
Tl;dr I want to query documents with the $all operator on the participantsIds field but the ownerId should be included in this query.
What I want is instead of querying against:
participantsIds: ['5f57ff55202b0e00065fbd14', '5f57ff55202b0e00065fbd15', '5f57ff55202b0e00065fbd13']
I want to query against:
participantsIds: ['5f57ff55202b0e00065fbd14', '5f57ff55202b0e00065fbd15', '5f57ff55202b0e00065fbd13', '5f57ff55202b0e00065fbd10']
Having fun here, by the way, it's better to use Joe answer if you are doing the query frequently, or even better a "All" field on insertion.
Additional Notes: Use projection at the start/end, to get what you need
https://mongoplayground.net/p/UP_-IUGenGp
db.collection.aggregate([
{
"$addFields": {
"all": {
$setUnion: [
"$participantsIds",
[
"$ownerId"
]
]
}
}
},
{
$match: {
all: {
$all: [
"5f57ff55202b0e00065fbd14",
"5f57ff55202b0e00065fbd15",
"5f57ff55202b0e00065fbd13",
"5f57ff55202b0e00065fbd10"
]
}
}
}
])
Didn't fully understand what you want to do but maybe this helps:
db.collection.find({
ownerId: "5f57ff55202b0e00065fbd10",
participantsIds: {
$all: ['5f57ff55202b0e00065fbd14',
'5f57ff55202b0e00065fbd15',
'5f57ff55202b0e00065fbd13']
})
You could use the pipeline form of update to either add the owner to the participant list or add a new consolidated field:
db.collection.update({},[{$set:{
allParticipantsIds: {$setUnion: [
"$participantsIds",
["$ownerId"]
]}
}}])
I'd like to be able to pull a document by id from a triple nested array of documents. DB looks something like this:
[{
type: "Foods",
fruit: [{
name: "Apple",
kinds: [{
name: "Red Delicious"
details: [{
_id: ObjectId("123123123"),
colors: ["red", "yellow"]
}]
}]
}]
}]
I'd like to be able to pull the document with the _id: 123123123. I've tried many different ways, but it always says it matches, but won't modify the document.
I've tried:
db.stuff.update({}, {$pull: {fruits: {kinds: {details: {_id: "123123123"}}}}}),
db.stuff.update({}, {$pull: {"fruits.kinds.details' : {_id: "123123123"}}}),
db.stuff.update({}, {$pull: {"fruits.$[].kinds.$[].details' : {_id: "123123123"}}})
But everytime it matches, but won't delete the document.
Please help.
The last attempt is correct however you need to fix two things: fruit instead of fruit (according to your sample data) and types needs to match so you have to convert string to ObjectId
db.stuff.update({}, {$pull: {"fruit.$[].kinds.$[].details' : {_id: mongoose.Types.ObjectId("123123123")}}})
Suppose, I have the following database:
{
_id: 1,
name: 'Alice',
courses: [
{
_id: 'DB103',
credits: 6
},
{
_id: 'ML203',
credits: 4
}
]
},
{
_id: 2,
name: 'Bob',
courses: []
}
I now want to 'upsert' the document with the course id 'DB103' in both documents. Although the _id field should remain the same, the credits field value should change (i.e. to 4). In the first document, the respective field should be changed, in the second one, {_id: 'DB103', credits: 4} should be inserted into the courses array.
Is there any possibility in MongoDB to handle both cases?
Sure, I could search with $elemMatch in courses for 'DB103' and if I haven't found it, insert, otherwise update the value. But these are two steps and I would like to do both in just one.
I have Item schema in which I have item details with respective restaurant. I have to find all items of particular restaurant and group by them with 'type' and 'category' (type and category are fields in Item schema), I am able to group items as I want but I wont be able to get complete item object.
My query:
db.items.aggregate([{
'$match': {
'restaurant': ObjectId("551111450712235c81620a57")
}
}, {
'$group': {
id: {
'$push': '$_id'
}
, _id: {
type: '$type'
, category: '$category'
}
}
}, {
$project: {
id: '$id'
}
}])
I have seen one method by adding each field value to group then project it. As I have many fields in my Item schema I don't feel this will good solution for me, Can I get complete object instead of Ids only.
Well you can always use $$ROOT providing that your server is MongoDB 2.6 or greater:
db.items.aggregate([
{ '$match': {'restaurant': ObjectId("551111450712235c81620a57")}},
{ '$group':{
_id : {
type : '$type',
category : '$category'
},
id: { '$push': '$$ROOT' },
}}
])
Which is going to place every whole object into the members of the array.
You need to be careful when doing this as with larger results you are certain to break BSON limits.
I would suggest that you are trying to contruct some kind of "search results", with "facet counts" or similar. For that you are better off running a separate query for the "aggregation" part and one for the actual document results.
That is a much safer and flexible approach than trying to group everything together.