I have following structure of my document:
{
"daily": [
{
"general": [
{
"status": false,
"_id": "5e728265f4796c0017203662",
"title": "Sport"
},...
]
}
]
}
I would like to pull the the document inside the "general" Array by it's "_id".
I tried several things but nothing seems to work for me.
Every help will be appreciate :)
The update query to pull the sub-document from the nested array field general using the _id:
ID = "5e728265f4796c0017203662"
db.collection.update(
{ "daily.general._id": ID },
{ $pull: { "daily.$.general": { _id: ID } } }
)
This can only be done in Mongo 4.2+, where they introduced pipeline'd updates.
Now we can use aggregation expressions to update documents:
db.collection.updateOne(
{},
[
{
$set: {
"daily": {
$map: {
input: "$daily",
as: "item",
in: {
"general": {
$filter: {
input: "$$item.general",
as: "datum",
cond: {$ne: ["$$datum._id", "5e728265f4796c0017203662"]}
}
}
}
}
}
}
}
]);
Or if objects in daily have more than just the general field you can do it like this:
db.collection.updateOne(
{},
[
{
$set: {
"daily": {
$map: {
input: "$daily",
as: "item",
in: {
$mergeObjects: [
"$$item",
{
"general": {
$filter: {
input: "$$item.general",
as: "datum",
cond: {$ne: ["$$datum._id", "5e728265f4796c0017203662"]}
}
}
}
]
}
}
}
}
}
]);
Unfortunately for any other Mongo version this is not possible, you'll have to restructure your data or do it in code.
Related
I am using Mongo 5.0.6 and have a document structured like this:
[
{
username: "admin",
properties: {
bookmarks: {
value: [
1,
2,
3
]
},
landmark: {
value: [
"home"
]
},
other: {
value: "should not show"
}
}
}
]
I need to query data based on the properties keys, this works fine in my mongo playground: https://mongoplayground.net/p/lEiLeStWGTn when I query for key that contain mark.
db.collection.aggregate([
{
$match: {
username: "admin"
}
},
{
$addFields: {
filtered: {
$filter: {
input: {
$objectToArray: "$properties"
},
cond: {
$regexMatch: {
input: "$$this.k",
regex: "mark"
}
}
}
}
}
},
{
$project: {
_id: 0,
properties: {
$arrayToObject: "$filtered"
}
}
}
])
However when I use it through my mongoose object I get [] even so the data is exactly as in playground. I am using locally the latest mongoose6 and mondodb5.0.6. I get the same [] result when I run the query against a mongodb.com hosted database. What could be the problem?
My javascript query below, I tried both using mongoose and the driver directly, as shown below:
const data= User.collection.aggregate([
{
$match: {
username: "admin"
}
},
{
$addFields: {
filtered: {
$filter: {
input: {
$objectToArray: "$properties"
},
cond: {
$regexMatch: {
input: "$$this.k",
regex: "mark"
}
}
}
}
}
},
{
$project: {
_id: 0,
properties: {
$arrayToObject: "$filtered"
}
}
}
]);
for await (const doc of data) {
console.log(doc);
}
Always gives me:
{ properties: {} }
When I take out the $addFields and $project like this:
const data= User.collection.aggregate([
{
$match: {
username: "admin"
}
}
]);
for await (const doc of data) {
console.log(doc);
}
I get, so the data is there, but aggregation pipeline isn't working:
[
{
_id: "61b9f2f5d2a6021365aae6d6",
username: "admin",
properties: {
bookmarks: {
value: [
1,
2,
3
]
},
landmark: {
value: [
"home"
]
},
other: {
value: "should not show"
}
}
}
]
So the data is there. What am I missing? Do I need to write the query differently?
I'm trying to display a MongoDB aggregation result via react chartjs. in aggregation, I can remove one field whose value is static via the set operator. is there a way to remove a second field by an association whose value is dynamic? in the example below, {"A": "N"} denotes the field that is readily removed by the set operator, whereas {"A_count":1} denotes the corresponding dynamic field that I am trying to remove.
starting aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"},{"A":"N"}],
"A_count_set":[{"A_count":0},{"A_count":1}]
}]
set operation for static field removal
{$set: {
A_set: {
$filter: {
input: "$A_set",
as: "x",
cond: { "$ne": [ "$$x", {"A":"N"}] }
}
}
}}
current aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"}],
"A_count_set":[{"A_count":0},{"A_count":1}]
}]
target aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"}],
"A_count_set":[{"A_count":0}]
}]
$project merge two array with the same position
$set filter array
$addFields recover the original array
$project remove the merge array
aggregate
db.collection.aggregate([
{
$project: {
anotherValue: {
$map: {
input: {
$range: [
0,
{
$size: "$A_set"
}
]
},
as: "idx",
in: {
$mergeObjects: [
{
$arrayElemAt: [
"$A_set",
"$$idx"
]
},
{
$arrayElemAt: [
"$A_count_set",
"$$idx"
]
}
]
}
}
}
}
},
{
$set: {
anotherValue: {
$filter: {
input: "$anotherValue",
as: "x",
cond: {
"$ne": [
"$$x.A",
"N"
]
}
}
}
}
},
{
$addFields: {
"A_set": {
$map: {
input: "$anotherValue",
as: "a",
in: {
"A": "$$a.A"
}
}
},
"A_count_set": {
$map: {
input: "$anotherValue",
as: "a",
in: {
"A_count": "$$a.A_count"
}
}
}
}
},
{
"$project": {
"anotherValue": 0
}
}
])
mongoplayground
Example of the document:
{
postId:'232323',
post:'This is my first post',
commentsOnPost:[
{
commentId:'232323_8888',
comment:'Congrats',
repliesOnPost:[
{
replyId:'232323_8888_66666',
reply:'Thanks',
likesOnReply:['user1','user5','user3'],
}
]
}
]
}
I want to add userid in likesOnReply if users do not exist in likesOnReply, similarly remove userid from likesOnReply if exist.
I have tried like this but not working properly
await collection('post').findOneAndUpdate(
{
postId: postId,
'commentsOnPost.commentId': commentId,
'commentsOnPost.repliesOnPost.replyId': replyId
},
{
$push: { 'commentsOnPost.$[].repliesOnPost.$.likes': userid },
},
);
There is no straight way to do both the operation to pull or push in a single query,
There are 2 approaches,
1) Find and update using 2 queries:
use arrayFilters to updated nested array elements
$push to insert element
$pull to remove element
var post = await collection('post').findOne({
posted: postId,
ommentsOnPost: {
$elemMatch: {
commentId: commentId,
repliesOnPost: {
$elemMatch: {
replyId: replyId
likesOnReply: userid
}
}
}
}
});
var updateOperator = "$push";
// FOUND USER ID THEN DO REMOVE OPERATION
if (post) updateOperator = "$pull";
// QUERY
await collection('post').updateOne(
{ postId: postId },
{
[updateOperator]: {
"commentsOnPost.$[c].repliesOnPost.$[r].likesOnReply": userid
}
},
{
arrayFilters: [
{ "c.commentId": commentId },
{ "r.replyId": replyId }
]
}
)
Playground
2) Update with aggregation pipeline starting from MongoDB 4.2:
$map to iterate loop of commentsOnPost array check condition if commentId match then go to next process otherwise return existing object
$mergeObjects to merge current object with updated fields
$map to iterate loop of repliesOnPost array and check condition if replyId match then go to next process otherwise return an existing object
check condition for likesOnReply has userid then do remove using $filter otherwise insert using $concatArrays
await collection('post').findOneAndUpdate(
{ postId: "232323" },
[{
$set: {
commentsOnPost: {
$map: {
input: "$commentsOnPost",
in: {
$cond: [
{ $eq: ["$$this.commentId", commentId] },
{
$mergeObjects: [
"$$this",
{
repliesOnPost: {
$map: {
input: "$$this.repliesOnPost",
in: {
$cond: [
{ $eq: ["$$this.replyId", replyId] },
{
$mergeObjects: [
"$$this",
{
likesOnReply: {
$cond: [
{ $in: [userid, "$$this.likesOnReply"] },
{
$filter: {
input: "$$this.likesOnReply",
cond: { $ne: ["$$this", userid] }
}
},
{
$concatArrays: ["$$this.likesOnReply", [userid]]
}
]
}
}
]
},
"$$this"
]
}
}
}
}
]
},
"$$this"
]
}
}
}
}
}]
)
Playgorund
I have a mongodb with some JSON data which includes and nested arrays. I am
trying to make a query to count how many documents have a specific
value. For example here is how my json data looks:
{
"_id" : ObjectId("5ecb815bf4b8512918224e71"),
"array1" : [
{
"_id" : ObjectId("5ecb815bf4b8512918224e85"),
"xxxx" : "1450",
"yyyy" : 83,
"array2" : [
{
"_id" : ObjectId("5ecb815bf4b8512918224e88"),
"aaaa" : "1470420945276",
},
{...},
{...}]
}
The query that i am trying is the following:
db.example.aggregate([
{
$project: {
value1: {
$filter: {
input: "$array1",
as: "array",
cond: { $eq: [ "$$array.array2.aaaa" , "1470420945276" ] }
}
}
}
},
{
$project: {
value1Count: { $size: "$value1" }
}
}
])
But doesnt work and returns that value1Count=0. It looks like it doesnt nnavigate into the array2 to
read the value of the 'aaaa'. Any help?
You were almost close to getting the desired value. The problem is $$array.array2.aaaa returns an array value, so we can't use $eq here. Instead, we should use $in operator.
db.example.aggregate([
{
$project: {
value1: {
$filter: {
input: "$array1",
as: "array",
cond: {
$in: [
"1470420945276",
"$$array.array2.aaaa"
]
}
}
}
}
},
{
$project: {
value1Count: {
$size: "$value1"
}
}
}
])
MongoPlayground | Alternative solution
So these are my two documents
Order document:
{
"_id":"02a33b9a-284c-4869-885e-d46981fdd679",
"context":{
"products":[
{
"id": "e68fc86a-b4ad-4588-b182-ae9ee3db25e4",
"version": "2020-03-14T13:18:41.296+00:00"
}
],
},
}
Product document:
{
"_id":"e68fc86a-b4ad-4588-b182-ae9ee3db25e4",
"context":{
"name": "My Product",
"image": "someimage"
},
}
So I'm trying to do a lookup for a products in order document, but the result should contain combined fields, like so:
"products":[
{
"_id": "e68fc86a-b4ad-4588-b182-ae9ee3db25e4",
"version": "2020-03-14T13:18:41.296+00:00",
"name": "My Product",
"image": "someimage"
}
],
Not sure how to do this, should I do it outside of the lookup, or inside? This is my aggregation
Orders.aggregate([
{
"$lookup":{
"from":"products",
"let":{
"products":"$context.products"
},
"pipeline":[
{
"$match":{
"$expr":{
"$in":[
"$_id",
"$$products.id"
]
}
}
},
{
"$project":{
"_id":0,
"id":1,
"name":"$context.name"
}
}
],
"as":"mergedProducts"
}
},
{
"$project":{
"context":"$context",
"mergedProducts":"$mergedProducts"
}
},
]);
You need to run that mapping outside of $lookup by running $map along with $arrayElemAt to get single pair from both arrays and then apply $mergeObjects to get one object as a result:
db.Order.aggregate([
{
$lookup: {
from: "products",
localField: "context.products.id",
foreignField: "_id",
as: "productDetails"
}
},
{
$addFields: {
productDetails: {
$map: {
input: "$productDetails",
in: {
_id: "$$this._id",
name: "$$this.context.name"
}
}
}
}
},
{
$project: {
_id: 1,
"context.products": {
$map: {
input: "$context.products",
as: "prod",
in: {
$mergeObjects: [
"$$prod",
{ $arrayElemAt: [ { $filter: { input: "$productDetails", cond: { $eq: [ "$$this._id", "$$prod.id" ] } } }, 0 ] }
]
}
}
}
}
}
])
Mongo Playground
The goals of the last step is to take take two arrays: products and productDetails (the output of $lookup) and find matches between them. We know there's always one match so we can get only one item $arrayElemAt 0. As an output of $map there will be single array containing "merged" documents.