I have a document structure like
{
"_id" : ObjectId("52263922f5ebf05115bf550e"),
"Fields" : [
{
"Field" : "Lot No",
"Rules" : [ ]
},
{
"Field" : "RMA No",
"Rules" : [ ]
}
]
}
I have tried to update by using the following code to push into the Rules Array which will hold objects.
db.test.update({
"Fields.Field":{$in:["Lot No"]}
}, {
$addToSet: {
"Fields.Field.$.Rules": {
"item_name": "my_item_two",
"price": 1
}
}
}, false, true);
But I get the following error:
can't append to array using string field name [Field]
How do I do the update?
You gone too deep with that wildcard $. You match for an item in the Fields array, so you get a access on that, with: Fields.$. This expression returns the first match in your Fields array, so you reach its fields by Fields.$.Field or Fields.$.Result.
Now, lets update the update:
db.test.update({
"Fields.Field": "Lot No"
}, {
$addToSet: {
"Fields.$.Rules": {
'item_name': "my_item_two",
'price':1
}
}
}, false, true);
Please note that I've shortened the query as it is equal to your expression.
Related
I'm struggling to write a Mongo UpdateMany statement that can reference and update an object within an array.
Here I create 3 documents. Each document has an array called innerArray always containing a single object, with a single date field.
use test;
db.innerArrayExample.insertOne({ _id: 1, "innerArray": [ { "originalDateTime" : ISODate("2022-01-01T01:01:01Z") } ]});
db.innerArrayExample.insertOne({ _id: 2, "innerArray": [ { "originalDateTime" : ISODate("2022-01-02T01:01:01Z") } ]});
db.innerArrayExample.insertOne({ _id: 3, "innerArray": [ { "originalDateTime" : ISODate("2022-01-03T01:01:01Z") } ]});
I want to add a new date field, based on the original date field, to end up with this:
{ _id: 1, "innerArray": [ { "originalDateTime" : ISODate("2022-01-01T01:01:01Z"), "copiedDateTime" : ISODate("2022-01-01T12:01:01Z") } ]}
{ _id: 2, "innerArray": [ { "originalDateTime" : ISODate("2022-01-02T01:01:01Z"), "copiedDateTime" : ISODate("2022-01-02T12:01:01Z") } ]}
{ _id: 3, "innerArray": [ { "originalDateTime" : ISODate("2022-01-03T01:01:01Z"), "copiedDateTime" : ISODate("2022-01-03T12:01:01Z") } ]}
In pseudo code I am saying take the originalDateTime, run it through a function and add a related copiedDateTime value.
For my specific use-case, the function I want to run strips the timezone from originalDateTime, then overwrites it with a new one, equivalent to the Java ZonedDateTime function withZoneSameLocal. Aka 9pm UTC becomes 9pm Brussels (therefore effectively 7pm UTC). The technical justification and methodology were answered in another Stack Overflow question here.
The part of the query I'm struggling with, is the part that updates/selects data from an element inside an array. In my simplistic example, for example I have crafted this query, but unfortunately it doesn't work:
This function puts copiedDateTime in the correct place... but doesn't evaluate the commands to manipulate the date:
db.innerArrayExample.updateMany({ "innerArray.0.originalDateTime" : { $exists : true }}, { $set: { "innerArray.0.copiedDateTime" : { $dateFromString: { dateString: { $dateToString: { "date" : "$innerArray.0.originalDateTime", format: "%Y-%m-%dT%H:%M:%S.%L" }}, format: "%Y-%m-%dT%H:%M:%S.%L", timezone: "Europe/Paris" }}});
// output
{
_id: 1,
innerArray: [
{
originalDateTime: ISODate("2022-01-01T01:01:01.000Z"),
copiedDateTime: {
'$dateFromString': {
dateString: { '$dateToString': [Object] },
format: '%Y-%m-%dT%H:%M:%S.%L',
timezone: 'Europe/Paris'
}
}
}
]
}
This simplified query, also has the same issue:
b.innerArrayExample.updateMany({ "innerArray.0.originalDateTime" : { $exists : true }}, { $set: { "innerArray.0.copiedDateTime" : "$innerArray.0.originalDateTime" }});
//output
{
_id: 1,
innerArray: [
{
originalDateTime: ISODate("2022-01-01T01:01:01.000Z"),
copiedDateTime: '$innerArray.0.originalDateTime'
}
]
}
As you can see this issue looks to be separate from the other stack overflow question. Instead of being able changing timezones, it's about getting things inside arrays to update.
I plan to take this query, create 70,000 variations of it with different location/timezone combinations and run it against a database with millions of records, so I would prefer something that uses updateMany instead of using Javascript to iterate over each row in the database... unless that's the only viable solution.
I have tried putting $set in square brackets. This changes the way it interprets everything, evaluating the right side, but causing other problems:
test> db.innerArrayExample.updateMany({ "_id" : 1 }, [{ $set: { "innerArray.0.copiedDateTime" : "$innerArray.0.originalDateTime" }}]);
//output
{
_id: 1,
innerArray: [
{
'0': { copiedDateTime: [] },
originalDateTime: ISODate("2022-01-01T01:01:01.000Z")
}
]
}
Above it seems to interpret .0. as a literal rather than an array element. (For my needs I know the array only has 1 item at all times). I'm at a loss finding an example that meets my needs.
I have also tried experimenting with the arrayFilters, documented on my mongo updateMany documentation but I cannot fathom how it works with objects:
test> db.innerArrayExample.updateMany(
... { },
... { $set: { "innerArray.$[element].copiedDateTime" : "$innerArray.$[element].originalDateTime" } },
... { arrayFilters: [ { "originalDateTime": { $exists: true } } ] }
... );
MongoServerError: No array filter found for identifier 'element' in path 'innerArray.$[element].copiedDateTime'
test> db.innerArrayExample.updateMany(
... { },
... { $set: { "innerArray.$[0].copiedDateTime" : "$innerArray.$[element].originalDateTime" } },
... { arrayFilters: [ { "0.originalDateTime": { $exists: true } } ] }
... );
MongoServerError: Error parsing array filter :: caused by :: The top-level field name must be an alphanumeric string beginning with a lowercase letter, found '0'
If someone can help me understand the subtleties of the Mongo syntax and help me back on to the right path I'd be very grateful.
You want to be using pipelined updates, the issue you're having with the syntax you're using is that it does not allow the usage of aggregation operators and document field values.
Here is a quick example on how to do it:
db.collection.updateMany({},
[
{
"$set": {
"innerArray": {
$map: {
input: "$innerArray",
in: {
$mergeObjects: [
"$$this",
{
copiedDateTime: "$$this.originalDateTime"
}
]
}
}
}
}
}
])
Mongo Playground
folks. I'm working in Node.js with a MongoDB collection that has a field that is an array of objects, like so:
{_id: 'someIdNumber',
text: 'some text',
replies: [{_id: 'someReplyId', replyText: 'some reply text', password: 'somePassword'}, {...}]
I'm trying to update the replyText field of the replies array using the $[<identifier>] array update operator as shown in the MongoDB documentation: https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/ What I'm trying to do is as follows:
db.collection('collectionName').updateOne(
{ _id: ObjectID('whateverId') },
{ $set: { "replies.$[elem].replyText": "new text" } },
{
arrayFilters: [{ "elem._id": ObjectID(req.body.reply_id)}, {"elem.password": 'whateverPassword}]
},
(err, data) => {console.log('hooray, it worked')}
This throws an error, MongoError: Found multiple array filters with the same top-level field name elem. If I get rid of one of my arrayFilters, this fixes the error, but obviously at the expense of my filtering conditions.
The MongoDB documentation's example of this process, (I've shortened the collection students2 to a single document,) is as follows:
{
"_id" : 1,
"grades" : [
{ "grade" : 80, "mean" : 75, "std" : 6 },
{ "grade" : 85, "mean" : 100, "std" : 4 },
{ "grade" : 85, "mean" : 100, "std" : 6 }
]
}
db.students2.update(
{ },
{ $inc: { "grades.$[elem].std" : -1 } },
{ arrayFilters: [ { "elem.grade": { $gte: 80 }, "elem.std": { $gt: 5 } } ], multi: true }
)
The syntax is a tiny bit different because the documentation is using the Mongo shell method, not Node.js, but otherwise, it looks to me like I'm doing what the documentation says to do. I'm using updateOne and not update because I only want to update one document, and I'm not using multi for the same reason.
Any insight on how I could get this to work with both arrayFilters intact would be much appreciated.
Thanks for your time!
Got it! Unfortunately I cannot upvote the question/comment hence adding here for others to benefit. Thanks #LuosRestil and #typesafe for getting me to the fix. I had the same syntax error where I tried to add multiple expressions for the same field in the array for the arrayFilters. It should be once expression per field.
WRONG:
arrayFilters: [
{ "elemA.<fieldName1>": "value1" },
{ "elemA.<fieldName2>": "value2" },
{ "elemA.<fieldName3>": "value3" }
];
CORRECT:
arrayFilters: [
{
"elemA.<fieldName1>": "value1",
"elemA.<fieldName2>": "value2",
"elemA.<fieldName3>": "value3"
}
];
I am working on an express js application where I need to update a nested array.
1) Schema :
//Creating a mongoose schema
var userSchema = mongoose.Schema({
_id: {type: String, required:true},
name: String,
sensors: [{
sensor_name: {type: String, required:true},
measurements: [{time: String}]
}] });
2)
Here is the code snippet and explanation is below:
router.route('/sensors_update/:_id/:sensor_name/')
.post(function (req, res) {
User.findOneAndUpdate({_id:req.body._id}, {$push: {"sensors" :
{"sensor_name" : req.body.sensor_name , "measurements.0.time": req.body.time } } },
{new:true},function(err, newSensor) {
if (err)
res.send(err);
res.send(newSensor)
}); });
I am able to successfully update a value to the measurements array using the findOneAndUpdate with push technique but I'm failing when I try to add multiple measurements to the sensors array.
Here is current json I get if I get when I post a second measurement to the sensors array :
{
"_id": "Manasa",
"name": "Manasa Sub",
"__v": 0,
"sensors": [
{
"sensor_name": "ras",
"_id": "57da0a4bf3884d1fb2234c74",
"measurements": [
{
"time": "8:00"
}
]
},
{
"sensor_name": "ras",
"_id": "57da0a68f3884d1fb2234c75",
"measurements": [
{
"time": "9:00"
}
]
}]}
But the right format I want is posting multiple measurements with the sensors array like this :
Right JSON format would be :
{
"_id" : "Manasa",
"name" : "Manasa Sub",
"sensors" : [
{
"sensor_name" : "ras",
"_id" : ObjectId("57da0a4bf3884d1fb2234c74"),
"measurements" : [
{
"time" : "8:00"
}
],
"measurements" : [
{
"time" : "9:00"
}
]
}],
"__v" : 0 }
Please suggest some ideas regarding this. Thanks in advance.
You might want to rethink your data model. As it is currently, you cannot accomplish what you want. The sensors field refers to an array. In the ideal document format that you have provided, you have a single object inside that array. Then inside that object, you have two fields with the exact same key. In a JSON object, or mongo document in this context, you can't have duplicate keys within the same object.
It's not clear exactly what you're looking for here, but perhaps it would be best to go for something like this:
{
"_id" : "Manasa",
"name" : "Manasa Sub",
"sensors" : [
{
"sensor_name" : "ras",
"_id" : ObjectId("57da0a4bf3884d1fb2234c74"),
"measurements" : [
{
"time" : "8:00"
},
{
"time" : "9:00"
}
]
},
{
// next sensor in the sensors array with similar format
"_id": "",
"name": "",
"measurements": []
}],
}
If this is what you want, then you can try this:
User.findOneAndUpdate(
{ _id:req.body._id "sensors.sensor_name": req.body.sensor_name },
{ $push: { "sensors.0.measurements": { "time": req.body.time } } }
);
And as a side note, if you're only ever going to store a single string in each object in the measurements array, you might want to just store the actual values instead of the whole object { time: "value" }. You might find the data easier to handle this way.
Instead of hardcoding the index of the array it is possible to use identifier and positional operator $.
Example:
User.findOneAndUpdate(
{ _id: "Manasa" },
{ $push: { "sensors.$[outer].measurements": { "time": req.body.time } } }
{ "arrayFilters:" [{"outer._id": ObjectId("57da0a4bf3884d1fb2234c74")}]
);
You may notice than instead of getting a first element of the array I specified which element of the sensors array I would like to update by providing its ObjectId.
Note that arrayFilters are passed as the third argument to the update query as an option.
You could now make "outer._id" dynamic by passing the ObjectId of the sensor like so: {"outer._id": req.body.sensorId}
In general, with the use of identifier, you can get to even deeper nested array elements by following the same procedure and adding more filters.
If there was a third level nesting you could then do something like:
User.findOneAndUpdate(
{ _id: "Manasa" },
{ $push: { "sensors.$[outer].measurements.$[inner].example": { "time": req.body.time } } }
{ "arrayFilters:" [{"outer._id": ObjectId("57da0a4bf3884d1fb2234c74"), {"inner._id": ObjectId("57da0a4bf3884d1fb2234c74"}}]
);
You can find more details here in the answer written by Neil Lunn.
refer ::: positional-all
--- conditions :: { other_conditions, 'array1.array2.field_to_be_checked': 'value' }
--- updateData ::: { $push : { 'array1.$[].array2.$[].array3' : 'value_to_be_pushed' } }
Is it possible to return records based on the size of the array after $elemMatch has filtered it down?
For example, if I have many records in a collection like the following:
[
{
contents: [
{
name: "yorkie",
},
{
name: "dairy milk",
},
{
name: "yorkie",
},
]
},
// ...
]
And I wanted to find all records in which their contents field contained 2 array items with their name field equal to "yorkie", how would I do this? To clarify, the array could contain other items, but the criteria is met so long as 2 of those array items have the matching field:value.
I'm aware I can use $elemMatch (or contents.name) to return records where the array contains at least one item matching that name, and I'm aware I can also use $size to filter based on the exact number of array items in the record's field. Is there a way that they can be both combined?
Not in a find query, but it can be done with an aggregation:
db.test.aggregate([
{ "$match" : { "contents.name" : "yorkie" } },
{ "$unwind" : "$contents" },
{ "$match" : { "contents.name" : "yorkie" } },
{ "$group" : { "_id" : "$_id", "sz" : { "$sum" : 1 } } }, // use $first to include other fields
{ "$match" : { "sz" : { "$gte" : 2 } } }
])
I interpreted
the criteria is met so long as 2 of those array items have the matching field:value
as meaning the criteria is met if at least 2 array items have the matching value in name.
I know this thread is old, but today you can just use find
db.test.find({
"$expr": {
"$gt": [
{
"$reduce": {
"input": "$contents",
"initialValue": 0,
"in": {
"$cond": {
"if": {
"$eq": ["$$this.name", 'yorkie']
},
"then": {
"$add": ["$$value", 1]
},
"else": "$$value"
}
}
}
},
1
]
}
})
The reduce will do the trick here, and will return the number of objects that match the criteria
I'm trying to update a single subelement contained within an array in a mongodb document. I want to reference the field using its array index (elements within the array don't have any fields that I can guarantee will be unique identifiers). Seems like this should be easy to do, but I can't figure out the syntax.
Here's what I want to do in pseudo-json.
Before:
{
_id : ...,
other_stuff ... ,
my_array : [
{ ... old content A ... },
{ ... old content B ... },
{ ... old content C ... }
]
}
After:
{
_id : ...,
other_stuff ... ,
my_array : [
{ ... old content A ... },
{ ... NEW content B ... },
{ ... old content C ... }
]
}
Seems like the query should be something like this:
//pseudocode
db.my_collection.update(
{_id: ObjectId(document_id), my_array.1 : 1 },
{my_array.$.content: NEW content B }
)
But this doesn't work. I've spent way too long searching the mongodb docs, and trying different variations on this syntax (e.g. using $slice, etc.). I can't find any clear explanation of how to accomplish this kind of update in MongoDB.
As expected, the query is easy once you know how. Here's the syntax, in python:
db["my_collection"].update(
{ "_id": ObjectId(document_id) },
{ "$set": { 'documents.'+str(doc_index)+'.content' : new_content_B}}
)
Update of an array element referenced by an index (e.g. 1 ) in Mongo Shell can also be done by directly indicating the index value:
db.my_collection.update(
{_id : "document_id"},
{$set : {"my_array.1.content" : "New content B"}}
)
In mongo style, using '$' positional operator.
Check out this link for details.
db.my_collection.update(
{_id: ObjectId(document_id), my_array.1 : 1 },
{ $set: { "my_array.$.content" : "NEW content B" } }
)
When it's required to update an array element without knowing it's actual index but having a unique identifier of the element:
// Modify a comment in a bucket
db.POST_COMMENT.update(
{
"_id": ObjectId("5ec424a1ed1af85a50855964"),
"bucket.commentId": "5eaf258bb80a1f03cd97a3ad_lepf4f"
},
{
$set: {
"bucket.$.text": "Comment text changed",
"bucket.$.createdDate": ISODate("2015-12-11T14:12:00.000+0000")
}
}
)
Here "bucket.commentId" is the unique identifier of an array element.
A neat way to do it in Javascript, with backticks, is:
const index = 1;
... { $set: { [`myArray.${index}.value`]: "new content"} }, ...
db.my_collection.update(
{_id: ObjectId(document_id), my_array : { ... old content A ... } },
{ $set: { "my_array.$.content" : "NEW content B" } }
)
When it's required to update an array element without knowing it's an actual index but having a unique identifier of the element
db.getCollection('profiles').update(
{
'userId':'4360a380-1540-45d9-b902-200f2d346263',
'skills.name':'css'
},
{
$set: {'skills.$.proficiencyLevel': 5}
},
{
multi: true
}
)
If you want to update the authorName of the testimonial having _id = 60c4918d74c30165ba585c14 from the following document:
"business": {
"ownerId": "60a5ebad7432d91b853c0277",
"testimonials": [
{
"_id": "60c4912877dd5664f2201b08",
"authorName": "user1",
"authorBio": "User from 10 years",
"image": "user1/img1",
"review": "asdfiuahsdfpoiuashdpfoaspdlfkjn;alsfpuoh"
},
{
"_id": "60c4918d74c30165ba585c14",
"authorName": "user2",
"authorBio": "User from 3 years",
"image": "user/img1",
"review": "asdpfuahsfljnsadfoihsf."
}
],
"createdAt": "2021-06-11T20:12:56.666Z",
"updatedAt": "2021-06-12T11:11:56.696Z",
}
Then the following mongoose query works:
await BusinessModel.updateOne(
{
'_id': Mongoose.Types.ObjectId(businessId),
'testimonials._id': Mongoose.Types.ObjectId('60c4918d74c30165ba585c14')
},
{
$set: { 'testimonials.$.authorName' : 'new author name' }
}
);
Also refer to https://docs.mongodb.com/drivers/node/fundamentals/crud/write-operations/embedded-arrays/
You can use the updateOne function of mongoDB passing the index of the element in array, if the key of old content B is "value" per example:
[
...
"value" : "old content A"
"value" : "old content B"
"value" : "old content C"
...
]
the command should be like this:
db.collection.updateOne({"_id" : "...,"},{$set: {"my_array.1.value": "NEW content B"}})
If you have a "plain" array containing simple strings, this did the trick:
db.paintings.insertMany([
{_id: 1, colors: ["red", "blue", "green"]},
{_id: 2, colors: ["red", "yellow"]}
db.paintings.updateMany(
{colors: "red"},
{$set: {"colors.$": "magenta"}})
the positional $ operator acts as a placeholder for the first element that matches the query document
Source