In my Mlab mongo 3.2 database I have a collection that looks like this:
{
"_id": {
"$oid": "5752d....87985"
},
"name": "...etation",
"description": null,
"user_id": ".....",
"questions": [
{
"prompt": "The conclusions drawn seemed clear to most researchers, however, others were unconvinced, arguing that everything is open to ____________.",
"answer": "interpretation",
"created_at": "2014-11-09T14:59:38.154",
"updated_at": "2014-11-09T14:59:38.154",
"filled_answer": null
},
{
"id": 922,
"prompt": "His existential quest for Truth is in fact the key to his understanding and ____________ of the Bhagavad-Gītā.",
"answer": "interpretation",
"created_at": "2014-10-03T08:07:40.295",
"updated_at": "2014-10-03T08:07:40.295",
"filled_answer": null
},
}
There are two problems with the questions subdocument that I am struggling with:
Sometimes but not always there is a legacy "id" field that I want to $unset but my query is not working.
I want to add an _id ObjectID field where they do not already exist. Currently some have them and some don't.
I have tried a number of queries but none seem to work. For example:
db.droplets.updateMany({"questions.$._id": { $exists: false }},{ $set: {"questions.$._id": new ObjectId()}},{"multi": true, "upsert": true})
Mongo tells me "The positional operator did not find the match needed from the query"
Update
I have successfully found a way to delete all the questions using the following script:
db.droplets4.find().forEach(function (doc) {
doc.questions.forEach(function (question) {
if (question.id) {
delete question.id
}
});
db.droplets.save(doc);
});
But the same strategy is not working for adding Object IDs. This code does not work:
db.droplets4.find().forEach(function (doc) {
doc.questions.forEach(function (question) {
if (!question._id) { question._id = new ObjectId() }
});
db.droplets.save(doc);
});
This should work fine for you
db.droplets4.updateMany( {
"questions._id" : null
},{ $set: {"questions.$._id": new ObjectId()}},{"multi": true, "upsert": true})
Related
I have a collection in MongoDB containing search history of a user where each document is stored like:
"_id": "user1"
searchHistory: {
"product1": [
{
"timestamp": 1623482432,
"query": {
"query": "chocolate",
"qty": 2
}
},
{
"timestamp": 1623481234,
"query": {
"query": "lindor",
"qty": 4
}
},
],
"product2": [
{
"timestamp": 1623473622,
"query": {
"query": "table",
"qty": 1
}
},
{
"timestamp": 1623438232,
"query": {
"query": "ike",
"qty": 1
}
},
]
}
Here _id of document acts like a foreign key to the user document in another collection.
I have backend running on nodejs and this function is used to store a new search history in the record.
exports.updateUserSearchCount = function (userId, productId, searchDetails) {
let addToSetData = {}
let key = `searchHistory.${productId}`
addToSetData[key] = { "timestamp": new Date().getTime(), "query": searchDetails }
return client.db("mydb").collection("userSearchHistory").updateOne({ "_id": userId }, { "$addToSet": addToSetData }, { upsert: true }, async (err, res) => {
})
}
Now, I want to get search history of a user based on query only using the db.find().
I want something like this:
db.find({"_id": "user1", "searchHistory.somewildcard.query": "some query"})
I need a wildcard which will replace ".somewildcard." to search in all products searched.
I saw a suggestion that we should store document like:
"_id": "user1"
searchHistory: [
{
"key": "product1",
"value": [
{
"timestamp": 1623482432,
"query": {
"query": "chocolate",
"qty": 2
}
}
]
}
]
However if I store document like this, then adding search history to existing document becomes a tideous and confusing task.
What should I do?
It's always a bad idea to save values are keys, for this exact reason you're facing. It heavily limits querying that field, obviously the trade off is that it makes updates much easier.
I personally recommend you do not save these searches in nested form at all, this will cause you scaling issues quite quickly, assuming these fields are indexed you will start seeing performance issues when the arrays get's too large ( few hundred searches ).
So my personal recommendation is for you to save it in a new collection like so:
{
"user_id": "1",
"key": "product1",
"timestamp": 1623482432,
"query": {
"query": "chocolate",
"qty": 2
}
}
Now querying a specific user or a specific product or even a query substring is all very easily supported by creating some basic indexes. an "update" in this case would just be to insert a new document which is also much faster.
If you still prefer to keep the nested structure, then I recommend you do switch to the recommended structure you posted, as you mentioned updates will become slightly more tedious, but you can still do it quite easily using arrayFilters for updating a specific element or just using $push for adding a new search
I have code that uses existing collection that I want to update name field value which is present in taskMap key how i run with run liqubase changeset for that .
sample code :
"changes": [
{
"collectionName": "bulk_import_job_spec"
},
{
"findOneAndUpdate": {
{"_id": 101},
[{"$set": {"task_map": {"import": {"_id": 1, "name": "Category Association"}}}}]
},
{
"returnNewDocument": true
}
]
your questions is quite vague. Please provide some more details so that we can understand your issue.
I’ve been trying to update the data in my mongoDB.
I want to update all products with a new productName field.
my data looks something like:
{
"id": "12345",
"products": [{
"id": 0
"productCode": "test",
"status": "PENDING",
},
{
"id": 1
"productCode": "test",
"status": "COMPLETE",
}],
}
When I try the following. I get this error The positional operator did not find the match needed from the query.
db.customers.updateMany(
{ id: "12345" },
{ $set: {
"products.$.productName": "Name here" }
}
)
If I do account.0.productName then it’s fine and updates. I’m not sure why $ is not working for me
db.customers.updateMany(
{ id: "12345" },
{ $set: {
"products.0.productName": "Name here" }
}
)
Positional operator is not working because you are not using the array into the find (first object)
If you try this query it will work as expected because you have the position finding by products.id.
Otherwise, if you don't have the position into array where update, yo can't use $ operator in this way. You need this query:
db.collection.update({
"id": "12345",
},
{
"$set": {
"products.$[].newField": "test2"
}
},
{
"multi": true
})
Mongo playground example here
Using $[] you can reference the array and add the value into each object.
$[] docs here
It says:
The all positional operator $[] indicates that the update operator should modify all elements in the specified array field.
That's exactly we want :)
Hello Good Developers,
I am facing a situation in MongoDB where I've JSON Data like this
[{
"id": "GLOBAL_EDUCATION",
"general_name": "GLOBAL_EDUCATION",
"display_name": "GLOBAL_EDUCATION",
"profile_section_id": 0,
"translated": [
{
"con_lang": "US-EN",
"country_code": "US",
"language_code": "EN",
"text": "What is the highest level of education you have completed?",
"hint": null
},
{
"con_lang": "US-ES",
"country_code": "US",
"language_code": "ES",
"text": "\u00bfCu\u00e1l es su nivel de educaci\u00f3n?",
"hint": null
}...
{
....
}
]
I am projecting result using the following query :
db.collection.find({
},
{
_id: 0,
id: 1,
general_name: 1,
translated: {
$elemMatch: {
con_lang: "US-EN"
}
}
})
here's a fiddle for the same: https://mongoplayground.net/p/I99ZXBfXIut
I want those records who don't match $elemMatch don't get returned at all.
In the fiddle output, you can see that the second item doesn't have translated attribute, In this case, I don't want the second Item at all to be returned.
I am using Laravel as Backend Tech, I can filter out those records using PHP, but there are lots of records returned, and I think filtering using PHP is not the best option.
You need to use $elemMatch in the first parameter
db.collection.find({
translated: {
$elemMatch: {
con_lang: "IT-EN"
}
}
})
MongoPlayground
I have a document that looks like this:
{
"_id": 3,
"Slug": "slug",
"Title": "title",
"Authors": [
{
"Slug": "slug",
"Name": "name"
}
]
}
I want to update all Authors.Name based on Authors.Slug.
I tried this but it didn't work:
.update({"Authors.Slug":"slug"}, {$set: {"Authors.Name":"zzz"}});
What am I doing wrong here?
.update(Authors:{$elemMatch:{Slug:"slug"}}, {$set: {'Authors.$.Name':"zzz"}});
You can use update with array filters:
https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/#positional-update-arrayfilters
Probably something like this:
yourcollection.update(
{},
{
"$set": {
"Authors.$[element].Name": "zzz"
}
},
{
"multi": true,
"arrayFilters": [
{ "element.Slug": "slug" }
]
}
)
Ps.: it will not work in Robo3T as explained here: Mongodb 3.6.0-rc3 array filters not working?
However, you can try on a mongo shell with version >= 3.6.
yes, Rock's solution is working, P.S Notes is really helpful when trying Robo31..
If we want to update all
db.collection_name.update({}, {$set: {"Authors.$[].Name": "zzz"}})
If we want to update with matching object in an array
db.collection_name.update({}, {$set: {"Authors.$[i].Name": "zzz"}}, {arrayFilters: [{"i.Slug": "slug"}]})
Ref: https://jira.mongodb.org/browse/SERVER-1243