This question already has an answer here:
Update array with multiple conditions in mongodb
(1 answer)
Closed 4 years ago.
I don't know if it is possible.
I'm trying to do an automatic process to update all elements of a nested array in some documents. The array hasn't a fixed length.
Below is a simplified example of the collection:
{
"_id" : ObjectId("5ba2e413a4dd01725a658c63"),
"MyOwnID" : "123456789",
"MyArray" : [
{
Field1: 'FooName1',
Field2: 'FooSpec1',
FieldToUpdate: '...'
},
{
Field1: 'FooName1',
Field2: 'FooSpec2',
FieldToUpdate: '...'
},
{
... More elements ...
}
]
},
{
"_id" : ObjectId("5ba2e413a4dd01725a658c63"),
"MyOwnID" : "987654321",
"MyArray" : [
{
Field1: 'FooName1',
Field2: 'FooSpec1',
FieldToUpdate: '...'
},
{
Field1: 'FooName2',
Field2: 'FooSpec2',
FieldToUpdate: '...'
},
]
}
I tried and it worked for the first element:
Query for the second element:
db.getCollection('works').findOneAndUpdate(
{ MyOwnID: '123456789', '$and':[ { 'MyArray.Field1': 'FooName1' },{ 'MyArray.Field2': 'FooSpec1' } ] } ,
{ '$set': { 'MyArray.$.FieldToUpdate': 1234} }
)
But when I try to update the second element only the first is updated.
Query for the second element:
db.getCollection('works').findOneAndUpdate(
{ MyOwnID: '123456789', '$and':[ { 'MyArray.Field1': 'FooName1' },{ 'MyArray.Field2': 'FooSpec2' } ] } ,
{ '$set': { 'MyArray.$.FieldToUpdate': 4321} }
)
I tried with arrayFilters option and $elemMatch, both give me an error.
Any options?
You can try below query using $elemMatch
db.getCollection("works").findOneAndUpdate(
{
"MyOwnID": "123456789",
"MyArray": { "$elemMatch": { "Field1": "FooName1", "Field2": "FooSpec2" }}
},
{ "$set": { "MyArray.$.FieldToUpdate": 4321 }}
)
You tried with arrayFilters, but probably in a wrong way, becuse it's working with it. It's not very clear in mongoDB doc, but $[myRef] acts as a placeholder for arrayFilters. Knowing that, you can do this to achieve your goal :
db['01'].findOneAndUpdate(
{MyOwnID: '123456789'},
{$set:{"MyArray.$[object].FieldToUpdate":1234}},
{arrayFilters:[{ $and:[{'object.Field1': 'FooName1' },{ 'object.Field2': 'FooSpec1' }]}]}
)
Note that the unique document in arrayFilters is needed (with $and operator), because both conditions refer to the placeholder. If you put 2 conditions,
({arrayFilters:[{'object.Field1': 'FooName1' },{ 'object.Field2':
'FooSpec1' }]})
MongoDB will complain about two criteria with same base placeholder.
While the answer given by #Anthony Winzlet is right and works perfectly, it will only update the first array element matching conditions defined in $elemMatch, that's why i avoid to use it like that (unless having a unique index on including MyArray.Field1 and MyArray.Field2, you can't be sure that the matching element is unique in your array)
Related
I have an old list of products that store the descriptions in an array at index [0]. The model is set up as a string. So my plan is to extract that value and add it to a temporary field. Step 2 would be to take that value and copy it to the original field.
This is the 'wrong' product I want to fix.
{_id : 1 , pDescription : ['great product']},
{_id : 2 , pDescription : ['another product']}
All I want to is to change the array to a string like this:
{_id : 1 , pDescription : 'great product'},
{_id : 2 , pDescription : 'another product'}
I have tried this to create the temporary description:
Products.aggregate([
{
$match: {
pDescription: {
$type: "array"
}
}
},
{
$set: {
pDescTemp: {
$first: "$pDescription"
}
}
}
]).exec((err, r) => {
// do stuff here
});
The command works fine without the $first command.
The error reads: MongoError: Unrecognized expression '$first'
Any tips on how to fix this are appreciated!
Thanks!
I believe this is what you need to update your pDescription field to be equal to the first element of the array already stored as pDescription:
db.Products.updateMany({},
[
{
$set: {
pDescription: {
$arrayElemAt: [
"$pDescription",
0
]
}
}
}
])
Is there a way to conditionally $addToSet based on a specific key field in a subdocument on an array?
Here's an example of what I mean - given the collection produced by the following sample bootstrap;
cls
db.so.remove();
db.so.insert({
"Name": "fruitBowl",
"pfms" : [
{
"n" : "apples"
}
]
});
n defines a unique document key. I only want one entry with the same n value in the array at any one time. So I want to be able to update the pfms array using n so that I end up with just this;
{
"Name": "fruitBowl",
"pfms" : [
{
"n" : "apples",
"mState": 1111234
}
]
}
Here's where I am at the moment;
db.so.update({
"Name": "fruitBowl",
},{
// not allowed to do this of course
// "$pull": {
// "pfms": { n: "apples" },
// },
"$addToSet": {
"pfms": {
"$each": [
{
"n": "apples",
"mState": 1111234
}
]
}
}
}
)
Unfortunately, this adds another array element;
db.so.find().toArray();
[
{
"Name" : "fruitBowl",
"_id" : ObjectId("53ecfef5baca2b1079b0f97c"),
"pfms" : [
{
"n" : "apples"
},
{
"n" : "apples",
"mState" : 1111234
}
]
}
]
I need to effectively upsert the apples document matching on n as the unique identifier and just set mState whether or not an entry already exists. It's a shame I can't do a $pull and $addToSet in the same document (I tried).
What I really need here is dictionary semantics, but that's not an option right now, nor is breaking out the document - can anyone come up with another way?
FWIW - the existing format is a result of language/driver serialization, I didn't choose it exactly.
further
I've gotten a little further in the case where I know the array element already exists I can do this;
db.so.update({
"Name": "fruitBowl",
"pfms.n": "apples",
},{
$set: {
"pfms.$.mState": 1111234,
},
}
)
But of course that only works;
for a single array element
as long as I know it exists
The first limitation isn't a disaster, but if I can't effectively upsert or combine $addToSet with the previous $set (which of course I can't) then it the only workarounds I can think of for now mean two DB round-trips.
The $addToSet operator of course requires that the "whole" document being "added to the set" is in fact unique, so you cannot change "part" of the document or otherwise consider it to be a "partial match".
You stumbled on to your best approach using $pull to remove any element with the "key" field that would result in "duplicates", but of course you cannot modify the same path in different update operators like that.
So the closest thing you will get is issuing separate operations but also doing that with the "Bulk Operations API" which is introduced with MongoDB 2.6. This allows both to be sent to the server at the same time for the closest thing to a "contiguous" operations list you will get:
var bulk = db.so.initializeOrderedBulkOp();
bulk.find({ "Name": "fruitBowl", "pfms.n": "apples": }).updateOne({
"$pull": { "pfms": { "n": "apples" } }
});
bulk.find({ "Name": "fruitBowl" }).updateOne({
"$push": { "pfms": { "n": "apples", "state": 1111234 } }
})
bulk.execute();
That pretty much is your best approach if it is not possible or practical to move the elements to another collection and rely on "upserts" and $set in order to have the same functionality but on a collection rather than array.
I have faced the exact same scenario. I was inserting and removing likes from a post.
What I did is, using mongoose findOneAndUpdate function (which is similar to update or findAndModify function in mongodb).
The key concept is
Insert when the field is not present
Delete when the field is present
The insert is
findOneAndUpdate({ _id: theId, 'likes.userId': { $ne: theUserId }},
{ $push: { likes: { userId: theUserId, createdAt: new Date() }}},
{ 'new': true }, function(err, post) { // do the needful });
The delete is
findOneAndUpdate({ _id: theId, 'likes.userId': theUserId},
{ $pull: { likes: { userId: theUserId }}},
{ 'new': true }, function(err, post) { // do the needful });
This makes the whole operation atomic and there are no duplicates with respect to the userId field.
I hope this helpes. If you have any query, feel free to ask.
As far as I know MongoDB now (from v 4.2) allows to use aggregation pipelines for updates.
More or less elegant way to make it work (according to the question) looks like the following:
db.runCommand({
update: "your-collection-name",
updates: [
{
q: {},
u: {
$set: {
"pfms.$[elem]": {
"n":"apples",
"mState": NumberInt(1111234)
}
}
},
arrayFilters: [
{
"elem.n": {
$eq: "apples"
}
}
],
multi: true
}
]
})
In my scenario, The data need to be init when not existed, and update the field If existed, and the data will not be deleted. If the datas have these states, you might want to try the following method.
// Mongoose, but mostly same as mongodb
// Update the tag to user, If there existed one.
const user = await UserModel.findOneAndUpdate(
{
user: userId,
'tags.name': tag_name,
},
{
$set: {
'tags.$.description': tag_description,
},
}
)
.lean()
.exec();
// Add a default tag to user
if (user == null) {
await UserModel.findOneAndUpdate(
{
user: userId,
},
{
$push: {
tags: new Tag({
name: tag_name,
description: tag_description,
}),
},
}
);
}
This is the most clean and fast method in the scenario.
As a business analyst , I had the same problem and hopefully I have a solution to this after hours of investigation.
// The customer document:
{
"id" : "1212",
"customerCodes" : [
{
"code" : "I"
},
{
"code" : "YK"
}
]
}
// The problem : I want to insert dateField "01.01.2016" to customer documents where customerCodes subdocument has a document with code "YK" but does not have dateField. The final document must be as follows :
{
"id" : "1212",
"customerCodes" : [
{
"code" : "I"
},
{
"code" : "YK" ,
"dateField" : "01.01.2016"
}
]
}
// The solution : the solution code is in three steps :
// PART 1 - Find the customers with customerCodes "YK" but without dateField
// PART 2 - Find the index of the subdocument with "YK" in customerCodes list.
// PART 3 - Insert the value into the document
// Here is the code
// PART 1
var myCursor = db.customers.find({ customerCodes:{$elemMatch:{code:"YK", dateField:{ $exists:false} }}});
// PART 2
myCursor.forEach(function(customer){
if(customer.customerCodes != null )
{
var size = customer.customerCodes.length;
if( size > 0 )
{
var iFoundTheIndexOfSubDocument= -1;
var index = 0;
customer.customerCodes.forEach( function(clazz)
{
if( clazz.code == "YK" && clazz.changeDate == null )
{
iFoundTheIndexOfSubDocument = index;
}
index++;
})
// PART 3
// What happens here is : If i found the indice of the
// "YK" subdocument, I create "updates" document which
// corresponds to the new data to be inserted`
//
if( iFoundTheIndexOfSubDocument != -1 )
{
var toSet = "customerCodes."+ iFoundTheIndexOfSubDocument +".dateField";
var updates = {};
updates[toSet] = "01.01.2016";
db.customers.update({ "id" : customer.id } , { $set: updates });
// This statement is actually interpreted like this :
// db.customers.update({ "id" : "1212" } ,{ $set: customerCodes.0.dateField : "01.01.2016" });
}
}
}
});
Have a nice day !
Here is an example of a document from the collection I am querying
meteor:PRIMARY> db.research.findOne({_id: 'Z2zzA7dx6unkzKiSn'})
{
"_id" : "Z2zzA7dx6unkzKiSn",
"_userId" : "NtE3ANq2b2PbWSEqu",
"collaborators" : [
{
"userId" : "aTPzFad8DdFXxRrX4"
}
],
"name" : "new one",
"pending" : {
"collaborators" : [ ]
}
}
I want to find all documents within this collection with either _userId: 'aTPzFad8DdFXxRrX4' or from the collaborators array, userId: 'aTPzFad8DdFXxRrX4'
So I want to look though the collection and check if the _userId field is 'aTPzFad8DdFXxRrX4'. If not then check the collaborators array on the document and check if there is an object with userId: 'aTPzFad8DdFXxRrX4'.
Here is the query I am trying to use:
db.research.find({$or: [{_userId: 'aTPzFad8DdFXxRrX4'}, {collaborators: {$in: [{userId: 'aTPzFad8DdFXxRrX4'}]}}] })
It does not find the document and gives me a syntax error. What is my issue here? Thanks
The $in operator is basically a simplified version of $or but you really only have one argument here so you should not even need it. Use dot notation instead:
db.research.find({
'$or': [
{ '_userId': 'aTPzFad8DdFXxRrX4'},
{ 'collaborators.userId': 'aTPzFad8DdFXxRrX4'}
]
})
If you need more than one value then use $in:
db.research.find({
'$or': [
{ '_userId': 'aTPzFad8DdFXxRrX4'},
{ 'collaborators.userId': {
'$in': ['aTPzFad8DdFXxRrX4','aTPzFad8DdFXxRrX5']
}}
]
})
The documents in my collection have the following format:
{ word: 'apple', number: 5 }
I want to increment the value of number from a javascript function. Yes, I know you can do that with a simple upsert, but I'm planning to do this for arrays and more complicated decisions that can't expressed by operators in a single upsert. This is just a simplified example.
What I've tried so far:
db.a.find({word:'test'})
{ "_id" : ObjectId("53c98ff18b95662af1148ad7"), "word" : "test", "number" : 5 }
db.a.find({word:'test'}).forEach(function(entry) {
inc: entry.number, 5;
print("test", entry.number);
})
test 5
(but it should be 10)
Could you please tell me what am I doing wrong?
db.runCommand({
findAndModify: "people",
query: { name: "Andy" },
sort: { rating: 1 },
update: { $inc: { score: 1 } },
upsert: true
})
As per my comment above. This should work in bulk operations as opposed to an update on each foreach iteration.
I just upgraded to Mongo 2.6.1 and one update statement that was working before is not returning an error. The update statement is:
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$.comments.$.name': 'joe'
}},
{ multi: true }
)
The error I get is:
WriteResult({
"nMatched" : 0,
"nUpserted" : 0,
"nModified" : 0,
"writeError" : {
"code" : 2,
"errmsg" : "Too many positional (i.e. '$') elements found in path 'answers.$.comments.$.createUsername'"
}
})
When I update an element just one level deep instead of two (i.e. answers.$.name instead of answers.$.comments.$.name), it works fine. If I downgrade my mongo instance below 2.6, it also works fine.
You CAN do this, you just need Mongo 3.6! Instead of redesigning your database, you could use the Array Filters feature in Mongo 3.6, which can be found here:
https://thecodebarbarian.com/a-nodejs-perspective-on-mongodb-36-array-filters
The beauty of this is that you can bind all matches in an array to a variable, and then reference that variable later. Here is the prime example from the link above:
Use arrayFilters.
MongoDB 3.5.12 extends all update modifiers to apply to all array
elements or all array elements that match a predicate, specified in a
new update option arrayFilters. This syntax also supports nested array
elements.
Let us assume a scenario-
"access": {
"projects": [{
"projectId": ObjectId(...),
"milestones": [{
"milestoneId": ObjectId(...),
"pulses": [{
"pulseId": ObjectId(...)
}]
}]
}]
}
Now if you want to add a pulse to a milestone which exists inside a project
db.users.updateOne({
"_id": ObjectId(userId)
}, {
"$push": {
"access.projects.$[i].milestones.$[j].pulses": ObjectId(pulseId)
}
}, {
arrayFilters: [{
"i.projectId": ObjectId(projectId)
}, {
"j.milestoneId": ObjectId(milestoneId)
}]
})
For PyMongo, use arrayFilters like this-
db.users.update_one({
"_id": ObjectId(userId)
}, {
"$push": {
"access.projects.$[i].milestones.$[j].pulses": ObjectId(pulseId)
}
}, array_filters = [{
"i.projectId": ObjectId(projectId)
}, {
"j.milestoneId": ObjectId(milestoneId)
}])
Also,
Each array filter must be a predicate over a document with a single
field name. Each array filter must be used in the update expression,
and each array filter identifier $[] must have a corresponding
array filter. must begin with a lowercase letter and not contain
any special characters. There must not be two array filters with the
same field name.
https://jira.mongodb.org/browse/SERVER-831
The positional operator can be used only once in a query. This is a limitation, there is an open ticket for improvement: https://jira.mongodb.org/browse/SERVER-831
As mentioned; more than one positional elements not supported for now. You may update with mongodb cursor.forEach() method.
db.post
.find({"answers.comments.name": "jeff"})
.forEach(function(post) {
if (post.answers) {
post.answers.forEach(function(answer) {
if (answer.comments) {
answer.comments.forEach(function(comment) {
if (comment.name === "jeff") {
comment.name = "joe";
}
});
}
});
db.post.save(post);
}
});
db.post.update(
{ 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$[i].comments.$.name': 'joe'
}},
{arrayFilters: [ { "i.comments.name": { $eq: 'jeff' } } ]}
)
check path after answers for get key path right
I have faced the same issue for the as array inside Array update require much performance impact. So, mongo db doest not support it. Redesign your database as shown in the given link below.
https://pythonolyk.wordpress.com/2016/01/17/mongodb-update-nested-array-using-positional-operator/
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$.comments.$.name': 'joe'
}},
{ multi: true }
)
Answer is
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.0.comments.1.name': 'joe'
}},
{ multi: true }
)