I am trying to match a record if one value is in an array of the document
OR other criteria are met. I don't get an error, but I get no records returned.
Any help appreciated (I have looked at other posts regarding arrays and aggregation - I could not get them to work either - so this is probably a duplicate, sorry)
Data:
_id:5c93f908aa338366bd00b966
name:"Davidson"
type:["G"]
_id:5c93f908aa338366bd00b977
name:"Robertson"
type:["G","R"]
Query:
thing.aggregate([{
$match: {
$or: [
{
"name": {
$regex: "xx",
$options: "i"
}
},
{
"type": {
$elemMatch: {
"type": "G"
}
}
}
]
}
}])
You don't need $elemMatch:
db.col.aggregate([{
$match: {
$or: [
{
"name": {
$regex: "xx",
$options: "i"
}
},
{
"type": "G"
}
]
}
}])
it checks if type array contains any "G"
Related
I want to update many documents based on the condition in MongoDB.
MODEL is the collection which has the document with below information.
"info": [
{
"field1": "String1",
"field2": "String2"
},
{
"field1": "String1",
"field2": "String_2"
}
],
"var": "x"
I need to update all the "String1" value of field1 with "STRING_NEW". I used the below query to update but not working as expected.
db.model.updateMany(
{ "info.field1": { $exists: true } },
[
{ "$set": {
"info": {
"$map": {
"input": "$info.field1",
"in": {
"$cond": [
{ "$eq": ["$$this.field1", "String1"] },
"STRING_NEW",
$$this.field1
]
}
}
}
} }
]
)
Please have a look and suggest if anything is to be modified in the above query.
Solution 1
With the update with aggregation pipeline, you should iterate the object in info array and update the iterated object by merging the current object with new field1 field via $mergeObjects.
db.model.updateMany({
"info.field1": "String1"
},
[
{
"$set": {
"info": {
"$map": {
"input": "$info",
"in": {
"$cond": [
{
"$eq": [
"$$this.field1",
"String1"
]
},
{
$mergeObjects: [
"$$this",
{
"field1": "STRING_NEW"
}
]
},
"$$this"
]
}
}
}
}
}
])
Demo Solution 1 # Mongo Playground
Solution 2
Can also work with $[<identifier>] positional filtered operator and arrayFilters.
db.model.updateMany({
"info.field1": "String1"
},
{
"$set": {
"info.$[info].field1": "STRING_NEW"
}
},
{
arrayFilters: [
{
"info.field1": "String1"
}
]
})
Demo Solution 2 # Mongo Playground
I have MongoDB documents structured in this way:
[
{
"id": "car_1",
"arrayProperty": [
{
"model": "sedan",
"turbo": "nil"
},
{
"model": "sedan",
"turbo": "60cc"
}
]
},
{
"id": "car_2",
"arrayProperty": [
{
"model": "coupe",
"turbo": "50cc"
},
{
"model": "coupe",
"turbo": "60cc"
}
]
}
]
I want to be able to make a find query that translates into basic English as "Ignoring all models that have 'nil' value for 'turbo', return all documents with arrayProperty of length X." That is to say, the "arrayProperty" of car 1 would be interpreted as having a size of 1, while the array of car 2 would have a size of 2. The goal is to be able to make a query for all cars with arrayProperty size of 2 and only see car 2 returned in the results.
Without ignoring the nil values, the query is very simple as:
{ arrayProperty: { $size: 2} }
And this would return both cars 1 and 2. Moreover, if our array was just a simple array such as:
[1,2,3,'nil]
Then our query is simply:
{
arrayProperty: {
$size: X,
$ne: "nil"
}
}
However, when we introduce an array of JSON objects, things get tricky. I have tried numerous things to no avail including:
"arrayProperty": {
$size: 2,
$ne: {"turbo": "nil"}
}
"arrayProperty": {
$size: 2,
$ne: ["arrayProperty.turbo": "nil"]
}
Even without the $size operator in there, I can't seem to filter by the nil value. Does anyone know how I would properly do this in those last two queries?
use $and in $match
db.collection.aggregate([
{
$match: {
"$and": [
{
arrayProperty: {
$size: 2
}
},
{
"arrayProperty.turbo": {
$ne: "nil"
}
}
]
}
}
])
mongoplayground
use $set first
db.collection.aggregate([
{
"$set": {
"arrayProperty": {
"$filter": {
"input": "$arrayProperty",
"as": "a",
"cond": {
$ne: [
"$$a.turbo",
"nil"
]
}
}
}
}
},
{
$match: {
arrayProperty: {
$size: 1
}
}
}
])
mongoplayground
set a new field of size
db.collection.aggregate([
{
"$set": {
"size": {
$size: {
"$filter": {
"input": "$arrayProperty",
"as": "a",
"cond": {
$ne: [
"$$a.turbo",
"nil"
]
}
}
}
}
}
},
{
$match: {
size: 1
}
}
])
mongoplayground
Consider the following document format which has an array field tasks holding embedded documents
{
"foo": "bar",
"tasks": [
{
"status": "sleep",
"id": "1"
},
{
"status": "active",
"id": "2"
}
]
}
There exists a partial index on key tasks.id
{
"v": 2,
"unique": true,
"key": {
"tasks.id": 1
},
"name": "tasks.id_1",
"partialFilterExpression": {
"tasks.id": {
"$exists": true
}
},
"ns": "zardb.quxcollection"
}
The following $elemMatch query with multiple conditions on the same array element
db.quxcollection.find(
{
"tasks": {
"$elemMatch": {
"id": {
"$eq": "1"
},
"status": {
"$nin": ["active"]
}
}
}
}).explain()
does not seem to use the index
"winningPlan": {
"stage": "COLLSCAN",
"filter": {
"tasks": {
"$elemMatch": {
"$and": [{
"id": {
"$eq": "1"
}
},
{
"status": {
"$not": {
"$eq": "active"
}
}
}
]
}
}
},
"direction": "forward"
}
How can I make the above query use the index? The index does seem to be used via dot notation
db.quxcollection.find({"tasks.id": "1"})
however I need the same array element to match multiple conditions which includes the status field, and the following does not seem to be equivalent to the above $elemMatch based query
db.quxcollection.find({
"tasks.id": "1",
"tasks.status": { "$nin": ["active"] }
})
The way the partial indexes work is it uses the path as a key. With $elemMatch you don't have the path explicitly in the query. If you check it with .explain("allPlansExecution") it is not even considered by the query planner.
To benefit from the index you can specify the path in the query:
db.quxcollection.find(
{
"tasks.id": "1",
"tasks": {
"$elemMatch": {
"id": {
"$eq": "1"
},
"status": {
"$nin": ["active"]
}
}
}
}).explain()
It duplicates part of the elemMatch condition, so the index will be used to get all documents containing tasks of specific id, then it will filter out documents with "active" tasks at fetch stage. I must admit the query doesn't look nice, so may be add some comments to the code with explanations.
tldr; I'm struggling to construct a query to
Make an aggregation to get a count of values on a certain key ("original_text_source"), which
Is in a sub-document that is in an array
Full description
I have embedded documents with arrays that are structured like this:
{
"_id" : ObjectId("0123456789"),
"type" : "some_object",
"relationships" : {
"x" : [ ObjectId("0123456789") ],
"y" : [ ObjectId("0123456789") ],
},
"properties" : [
{
"a" : "1"
},
{
"b" : "1"
},
{
"original_text_source" : "foo.txt"
},
]
}
The docs were created from exactly 10k text files, sorted in various folders. During inserting documents into the MongoDB (in batches) I messed up and moved a few files around, causing one file to be imported twice (my database has a count of exactly 10001 docs), but obviously I don't know which one it is. Since one of the "original_text_source" values has to have a count of 2, I was planning on just deleting one.
I read up on solutions with $elemMatch, but since my array element is a document, I'm not sure how to proceed. Maybe with mapReduce? But I can't transfer the logic to my doc structure.
I also could just create a new collection and reupload all, but in case I mess up again, I'd rather like to learn how to query for duplicates. It seems more elegant :-)
You can find duplicates with a simple aggregation like this:
db.collection.aggregate(
{ $group: { _id: "$properties.original_text_source", docIds: { $push: "$_id" }, docCount: { $sum: 1 } } },
{ $match: { "docCount": { $gt: 1 } } }
)
which gives you something like this:
{
"_id" : [
"foo.txt"
],
"docIds" : [
ObjectId("59d6323613940a78ba1d5ffa"),
ObjectId("59d6324213940a78ba1d5ffc")
],
"docCount" : 2.0
}
Run the following:
db.collection.aggregate([
{ $group: {
_id: { name: "$properties.original_text_source" },
idsForDuplicatedDocs: { $addToSet: "$_id" },
count: { $sum: 1 }
} },
{ $match: {
count: { $gte: 2 }
} },
{ $sort : { count : -1} }
]);
Given a collection which contains two copies of the document you showed in your question, the above command will return:
{
"_id" : {
"name" : [
"foo.txt"
]
},
"idsForDuplicatedDocs" : [
ObjectId("59d631d2c26584cd8b7b3337"),
ObjectId("59d631cbc26584cd8b7b3333")
],
"count" : 2
}
Where ...
The attribute _id.name is the value of the duplicated properties.original_text_source
The attribute idsForDuplicatedDocs contains the _id values for each of the documents which have a duplicated properties.original_text_source
"reviewAndRating": [
{
"review": "aksjdhfkashdfkashfdkjashjdkfhasdkjfhsafkjhasdkjfhasdjkfhsdakfj",
"productId": "5bd956f29fcaca161f6b7517",
"_id": "5bd9745e2d66162a6dd1f0ef",
"rating": "5"
},
{
"review": "aksjdhfkashdfkashfdkjashjdkfhasdkjfhsafkjhasdkjfhasdjkfhsdakfj",
"productId": "5bd956f29fcaca161f6b7518",
"_id": "5bd974612d66162a6dd1f0f0",
"rating": "5"
},
{
"review": "aksjdhfkashdfkashfdkjashjdkfhasdkjfhsafkjhasdkjfhasdjkfhsdakfj",
"productId": "5bd956f29fcaca161f6b7517",
"_id": "5bd974622d66162a6dd1f0f1",
"rating": "5"
}
]
I am trying to find elements from my MongoDB database with meteor.
I managed to filter and go through the structure of my array, but the result is a single element, and not all the elements matching the criteria.
Query :
var json = Tests1VerlIR.find({}, {fields: {entries: {$elemMatch: {'payload.id': {$eq: this.params._id}} } } }).fetch();
this.response.setHeader('Content-Type', 'application/json');
this.response.end(JSON.stringify(json));
Data Structure :
{"entries":
[{"method":"POST",
"source":"ex",
"path":"/ex",
"time":1464615406900,
"payload":
{"slot_frame_number":"4",
"slot_HTUTemp":"2306",
"data":"0400f008561655270209a314",
"slot_BMEPres":"10069",
"slot_HTUHumi":"5283",
"slot_BMETemp":"2288",
"time":"1464615404",
"device":"79",
"slot_BMEHumi":"5718",
"signal":"7.22",
"id":"2"},
"_id":"574c41ee578d01af3664cbaf"},
{"method":"POST",
"source":"ex",
"path":"/ex",
"time":1464615406900,
"payload":
{"slot_frame_number":"4",
"slot_HTUTemp":"2306",
"data":"0400f008561655270209a314",
"slot_BMEPres":"10069",
"slot_HTUHumi":"5283",
"slot_BMETemp":"2288",
"time":"1464615404",
"device":"79",
"slot_BMEHumi":"5718",
"signal":"7.22",
"id":"2"},
"_id":"574c41ee578d01af3664cbaf"}, {...}]}
Response :
[
{
"_id":
{
"_str": "576155d7a605348159cd1f1a"
},
"entries":
[
{
"method": "POST",
"source": "ex",
"path": "/ex",
"time": 1464615406900,
"payload":
{
"slot_frame_number":"4",
"slot_HTUTemp":"2306",
"data":"0400f008561655270209a314",
"slot_BMEPres":"10069",
"slot_HTUHumi":"5283",
"slot_BMETemp":"2288",
"time":"1464615404",
"device":"79",
"slot_BMEHumi":"5718",
"signal":"7.22",
"id":"2"
},
"_id": "574c41ee578d01af3664cbaf"
}
]
}
]
You cannot return multiple elements of an array matching your criteria in any form of a basic .find() query. To match more than one element you need to use the .aggregate() method instead.
refer this link.
Tests1VerlIR.aggregate([
{ "$match": { "entries.payload.id": "2" } },
// Unwind the array to denormalize
{ "$unwind": "$entries" },
// Match specific array elements
{ "$match": { "entries.payload.id": "2" } },
// Group back to array form
{ "$group": {
"_id": "$_id",
"entries": { "$push": "$entries" }
}}
])
Solution :
var json = Tests1VerlIR.aggregate({"$unwind": "$entries"}, {$match: {'entries.payload.id': this.params._id} });