Cannot infer query fields to set error on insert - javascript

I'm trying to achieve a "getOrCreate" behavior using "findAndModify".
I'm working in nodejs using the native driver.
I have:
var matches = db.collection("matches");
matches.findAndModify({
//query
users: {
$all: [ userA_id, userB_id ]
},
lang: lang,
category_id: category_id
},
[[ "_id", "asc"]], //order
{
$setOnInsert: {
users: [userA_id, userB_id],
category_id: category_id,
lang: lang,
status: 0
}
},
{
new:true,
upsert:true
}, function(err, doc){
//Do something with doc
});
What i was trying to do is:
"Find specific match with specified users, lang and category... if not found, insert a new one with specified data"
Mongo is throwing this error:
Error getting/creating match { [MongoError: exception: cannot infer query fields to set, path 'users' is matched twice]
name: 'MongoError',
message: 'exception: cannot infer query fields to set, path \'users\' is matched twice',
errmsg: 'exception: cannot infer query fields to set, path \'users\' is matched twice',
code: 54,
ok: 0 }
Is there a way to make it work?
It's impossible?
Thank you :)

It's not the "prettiest" way to handle this, but current restrictions on the selection operators mean you would need to use a JavaScript expression with $where.
Substituting your vars for values for ease of example:
matches.findAndModify(
{
"$where": function() {
var match = [1,2];
return this.users.filter(function(el) {
return match.indexOf(el) != -1;
}).length >= 2;
},
"lang": "en",
"category_id": 1
},
[],
{
"$setOnInsert": {
"users": [1,2],
"lang": "en",
"category_id": 1
}
},
{
"new": true,
"upsert": true
},
function(err,doc) {
// do something useful here
}
);
As you might suspect, the "culprit" here is the positional $ operator, even though your operation does not make use of it.
And the problem specifically is because of $all which is looking for the possible match at "two" positions in the array. In the event that a "positional" operator was required, the engine cannot work out ( presently ) which position to present. The position should arguably be the "first" match being consistent with other operations, but it is not currently working like that.
Replacing the logic with a JavaScript expression circumvents this as the JavaScript logic cannot return a matched position anyway. That makes the expression valid, and you can then either "create" and array with the two elements in a new document or retrieve the document that contains "both" those elements as well as the other query conditions.
P.S Little bit worried about your "sort" here. You may have added it because it is "mandatory" to the method, however if you do possibly expect this to match "more than one" document and need "sort" to work out which one to get then your logic is slightly flawed.
When doing this to "find or create" then you really need to specifiy "all" of the "unique" key constraints in your query. If you don't then you are likely to run into duplicate key errors down the track.
Sort can in fact be an empty array if you do not actually need to "pick" a result from many.
Just something to keep in mind.

Related

Why am I getting an error that my conditions don't match the schema?

I have this query that works:
{
"TableName": "myTable",
"IndexName": "gsi1",
"Limit": 12,
"KeyConditionExpression": "#pk = :pk",
"ExpressionAttributeValues": {
":pk": "TOS"
},
"ExpressionAttributeNames": {
"#pk": "gsi1_pk"
}
}
I attempted to convert it into one using KeyConditions instead of an expression because that makes other things easier. So I changed it to this:
{
"TableName": "myTable",
"IndexName": "gsi1",
"Limit": 12,
"KeyConditions": {
"gsi1_pk": {
"ComparisonOperator": "EQ",
"AttributeValueList": [
{
"S": "TOS"
}
]
}
}
}
I have the GSI configured on my table:
But when I make the request I'm getting this error:
ValidationException: One or more parameter values were invalid: Condition parameter type does not match schema type
I don't understand why I'm getting this error.
My Partition key for this GSI is a string
The only attribute I'm querying against is a string
The name gsi1_pk matches the value I'm querying
Did I miss something in converting this query? I don't understand what I should change to resolve the error because it looks accurate to me.
From this aws doc
This is a legacy parameter. Use KeyConditionExpression instead.
'KeyConditions' >= 'KeyConditionExpression'
Changing your key var in your query should fix this.

mongodb pull an array from several object in an array of one document [duplicate]

I have a Mongo document which holds an array of elements.
I'd like to reset the .handled attribute of all objects in the array where .profile = XX.
The document is in the following form:
{
"_id": ObjectId("4d2d8deff4e6c1d71fc29a07"),
"user_id": "714638ba-2e08-2168-2b99-00002f3d43c0",
"events": [{
"handled": 1,
"profile": 10,
"data": "....."
} {
"handled": 1,
"profile": 10,
"data": "....."
} {
"handled": 1,
"profile": 20,
"data": "....."
}
...
]
}
so, I tried the following:
.update({"events.profile":10},{$set:{"events.$.handled":0}},false,true)
However it updates only the first matched array element in each document. (That's the defined behaviour for $ - the positional operator.)
How can I update all matched array elements?
With the release of MongoDB 3.6 ( and available in the development branch from MongoDB 3.5.12 ) you can now update multiple array elements in a single request.
This uses the filtered positional $[<identifier>] update operator syntax introduced in this version:
db.collection.update(
{ "events.profile":10 },
{ "$set": { "events.$[elem].handled": 0 } },
{ "arrayFilters": [{ "elem.profile": 10 }], "multi": true }
)
The "arrayFilters" as passed to the options for .update() or even
.updateOne(), .updateMany(), .findOneAndUpdate() or .bulkWrite() method specifies the conditions to match on the identifier given in the update statement. Any elements that match the condition given will be updated.
Noting that the "multi" as given in the context of the question was used in the expectation that this would "update multiple elements" but this was not and still is not the case. It's usage here applies to "multiple documents" as has always been the case or now otherwise specified as the mandatory setting of .updateMany() in modern API versions.
NOTE Somewhat ironically, since this is specified in the "options" argument for .update() and like methods, the syntax is generally compatible with all recent release driver versions.
However this is not true of the mongo shell, since the way the method is implemented there ( "ironically for backward compatibility" ) the arrayFilters argument is not recognized and removed by an internal method that parses the options in order to deliver "backward compatibility" with prior MongoDB server versions and a "legacy" .update() API call syntax.
So if you want to use the command in the mongo shell or other "shell based" products ( notably Robo 3T ) you need a latest version from either the development branch or production release as of 3.6 or greater.
See also positional all $[] which also updates "multiple array elements" but without applying to specified conditions and applies to all elements in the array where that is the desired action.
Also see Updating a Nested Array with MongoDB for how these new positional operators apply to "nested" array structures, where "arrays are within other arrays".
IMPORTANT - Upgraded installations from previous versions "may" have not enabled MongoDB features, which can also cause statements to fail. You should ensure your upgrade procedure is complete with details such as index upgrades and then run
db.adminCommand( { setFeatureCompatibilityVersion: "3.6" } )
Or higher version as is applicable to your installed version. i.e "4.0" for version 4 and onwards at present. This enabled such features as the new positional update operators and others. You can also check with:
db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
To return the current setting
UPDATE:
As of Mongo version 3.6, this answer is no longer valid as the mentioned issue was fixed and there are ways to achieve this. Please check other answers.
At this moment it is not possible to use the positional operator to update all items in an array. See JIRA http://jira.mongodb.org/browse/SERVER-1243
As a work around you can:
Update each item individually
(events.0.handled events.1.handled
...) or...
Read the document, do the edits
manually and save it replacing the
older one (check "Update if
Current" if you want to ensure
atomic updates)
What worked for me was this:
db.collection.find({ _id: ObjectId('4d2d8deff4e6c1d71fc29a07') })
.forEach(function (doc) {
doc.events.forEach(function (event) {
if (event.profile === 10) {
event.handled=0;
}
});
db.collection.save(doc);
});
I think it's clearer for mongo newbies and anyone familiar with JQuery & friends.
This can also be accomplished with a while loop which checks to see if any documents remain that still have subdocuments that have not been updated. This method preserves the atomicity of your updates (which many of the other solutions here do not).
var query = {
events: {
$elemMatch: {
profile: 10,
handled: { $ne: 0 }
}
}
};
while (db.yourCollection.find(query).count() > 0) {
db.yourCollection.update(
query,
{ $set: { "events.$.handled": 0 } },
{ multi: true }
);
}
The number of times the loop is executed will equal the maximum number of times subdocuments with profile equal to 10 and handled not equal to 0 occur in any of the documents in your collection. So if you have 100 documents in your collection and one of them has three subdocuments that match query and all the other documents have fewer matching subdocuments, the loop will execute three times.
This method avoids the danger of clobbering other data that may be updated by another process while this script executes. It also minimizes the amount of data being transferred between client and server.
This does in fact relate to the long standing issue at http://jira.mongodb.org/browse/SERVER-1243 where there are in fact a number of challenges to a clear syntax that supports "all cases" where mutiple array matches are found. There are in fact methods already in place that "aid" in solutions to this problem, such as Bulk Operations which have been implemented after this original post.
It is still not possible to update more than a single matched array element in a single update statement, so even with a "multi" update all you will ever be able to update is just one mathed element in the array for each document in that single statement.
The best possible solution at present is to find and loop all matched documents and process Bulk updates which will at least allow many operations to be sent in a single request with a singular response. You can optionally use .aggregate() to reduce the array content returned in the search result to just those that match the conditions for the update selection:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$project": {
"events": {
"$setDifference": [
{ "$map": {
"input": "$events",
"as": "event",
"in": {
"$cond": [
{ "$eq": [ "$$event.handled", 1 ] },
"$$el",
false
]
}
}},
[false]
]
}
}}
]).forEach(function(doc) {
doc.events.forEach(function(event) {
bulk.find({ "_id": doc._id, "events.handled": 1 }).updateOne({
"$set": { "events.$.handled": 0 }
});
count++;
if ( count % 1000 == 0 ) {
bulk.execute();
bulk = db.collection.initializeOrderedBulkOp();
}
});
});
if ( count % 1000 != 0 )
bulk.execute();
The .aggregate() portion there will work when there is a "unique" identifier for the array or all content for each element forms a "unique" element itself. This is due to the "set" operator in $setDifference used to filter any false values returned from the $map operation used to process the array for matches.
If your array content does not have unique elements you can try an alternate approach with $redact:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$redact": {
"$cond": {
"if": {
"$eq": [ { "$ifNull": [ "$handled", 1 ] }, 1 ]
},
"then": "$$DESCEND",
"else": "$$PRUNE"
}
}}
])
Where it's limitation is that if "handled" was in fact a field meant to be present at other document levels then you are likely going to get unexepected results, but is fine where that field appears only in one document position and is an equality match.
Future releases ( post 3.1 MongoDB ) as of writing will have a $filter operation that is simpler:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$project": {
"events": {
"$filter": {
"input": "$events",
"as": "event",
"cond": { "$eq": [ "$$event.handled", 1 ] }
}
}
}}
])
And all releases that support .aggregate() can use the following approach with $unwind, but the usage of that operator makes it the least efficient approach due to the array expansion in the pipeline:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$unwind": "$events" },
{ "$match": { "events.handled": 1 } },
{ "$group": {
"_id": "$_id",
"events": { "$push": "$events" }
}}
])
In all cases where the MongoDB version supports a "cursor" from aggregate output, then this is just a matter of choosing an approach and iterating the results with the same block of code shown to process the Bulk update statements. Bulk Operations and "cursors" from aggregate output are introduced in the same version ( MongoDB 2.6 ) and therefore usually work hand in hand for processing.
In even earlier versions then it is probably best to just use .find() to return the cursor, and filter out the execution of statements to just the number of times the array element is matched for the .update() iterations:
db.collection.find({ "events.handled": 1 }).forEach(function(doc){
doc.events.filter(function(event){ return event.handled == 1 }).forEach(function(event){
db.collection.update({ "_id": doc._id },{ "$set": { "events.$.handled": 0 }});
});
});
If you are aboslutely determined to do "multi" updates or deem that to be ultimately more efficient than processing multiple updates for each matched document, then you can always determine the maximum number of possible array matches and just execute a "multi" update that many times, until basically there are no more documents to update.
A valid approach for MongoDB 2.4 and 2.2 versions could also use .aggregate() to find this value:
var result = db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$unwind": "$events" },
{ "$match": { "events.handled": 1 } },
{ "$group": {
"_id": "$_id",
"count": { "$sum": 1 }
}},
{ "$group": {
"_id": null,
"count": { "$max": "$count" }
}}
]);
var max = result.result[0].count;
while ( max-- ) {
db.collection.update({ "events.handled": 1},{ "$set": { "events.$.handled": 0 }},{ "multi": true })
}
Whatever the case, there are certain things you do not want to do within the update:
Do not "one shot" update the array: Where if you think it might be more efficient to update the whole array content in code and then just $set the whole array in each document. This might seem faster to process, but there is no guarantee that the array content has not changed since it was read and the update is performed. Though $set is still an atomic operator, it will only update the array with what it "thinks" is the correct data, and thus is likely to overwrite any changes occurring between read and write.
Do not calculate index values to update: Where similar to the "one shot" approach you just work out that position 0 and position 2 ( and so on ) are the elements to update and code these in with and eventual statement like:
{ "$set": {
"events.0.handled": 0,
"events.2.handled": 0
}}
Again the problem here is the "presumption" that those index values found when the document was read are the same index values in th array at the time of update. If new items are added to the array in a way that changes the order then those positions are not longer valid and the wrong items are in fact updated.
So until there is a reasonable syntax determined for allowing multiple matched array elements to be processed in single update statement then the basic approach is to either update each matched array element in an indvidual statement ( ideally in Bulk ) or essentially work out the maximum array elements to update or keep updating until no more modified results are returned. At any rate, you should "always" be processing positional $ updates on the matched array element, even if that is only updating one element per statement.
Bulk Operations are in fact the "generalized" solution to processing any operations that work out to be "multiple operations", and since there are more applications for this than merely updating mutiple array elements with the same value, then it has of course been implemented already, and it is presently the best approach to solve this problem.
First: your code did not work because you were using the positional operator $ which only identifies an element to update in an array but does not even explicitly specify its position in the array.
What you need is the filtered positional operator $[<identifier>]. It would update all elements that match an array filter condition.
Solution:
db.collection.update({"events.profile":10}, { $set: { "events.$[elem].handled" : 0 } },
{
multi: true,
arrayFilters: [ { "elem.profile": 10 } ]
})
Visit mongodb doc here
What the code does:
{"events.profile":10} filters your collection and return the documents matching the filter
The $set update operator: modifies matching fields of documents it acts on.
{multi:true} It makes .update() modifies all documents matching the filter hence behaving like updateMany()
{ "events.$[elem].handled" : 0 } and arrayFilters: [ { "elem.profile": 10 } ]
This technique involves the use of the filtered positional array with arrayFilters. the filtered positional array here $[elem] acts as a placeholder for all elements in the array fields that match the conditions specified in the array filter.
Array filters
You can update all elements in MongoDB
db.collectioname.updateOne(
{ "key": /vikas/i },
{ $set: {
"arr.$[].status" : "completed"
} }
)
It will update all the "status" value to "completed" in the "arr" Array
If Only one document
db.collectioname.updateOne(
 { key:"someunique", "arr.key": "myuniq" },
 { $set: {
   "arr.$.status" : "completed",
   "arr.$.msgs":  {
        "result" : ""
        }
   
 } }
)
But if not one and also you don't want all the documents in the array to update then you need to loop through the element and inside the if block
db.collectioname.find({findCriteria })
.forEach(function (doc) {
doc.arr.forEach(function (singlearr) {
if (singlearr check) {
singlearr.handled =0
}
});
db.collection.save(doc);
});
I'm amazed this still hasn't been addressed in mongo. Overall mongo doesn't seem to be great when dealing with sub-arrays. You can't count sub-arrays simply for example.
I used Javier's first solution. Read the array into events then loop through and build the set exp:
var set = {}, i, l;
for(i=0,l=events.length;i<l;i++) {
if(events[i].profile == 10) {
set['events.' + i + '.handled'] = 0;
}
}
.update(objId, {$set:set});
This can be abstracted into a function using a callback for the conditional test
The thread is very old, but I came looking for answer here hence providing new solution.
With MongoDB version 3.6+, it is now possible to use the positional operator to update all items in an array. See official documentation here.
Following query would work for the question asked here. I have also verified with Java-MongoDB driver and it works successfully.
.update( // or updateMany directly, removing the flag for 'multi'
{"events.profile":10},
{$set:{"events.$[].handled":0}}, // notice the empty brackets after '$' opearor
false,
true
)
Hope this helps someone like me.
I've been looking for a solution to this using the newest driver for C# 3.6 and here's the fix I eventually settled on. The key here is using "$[]" which according to MongoDB is new as of version 3.6. See https://docs.mongodb.com/manual/reference/operator/update/positional-all/#up.S[] for more information.
Here's the code:
{
var filter = Builders<Scene>.Filter.Where(i => i.ID != null);
var update = Builders<Scene>.Update.Unset("area.$[].discoveredBy");
var result = collection.UpdateMany(filter, update, new UpdateOptions { IsUpsert = true});
}
For more context see my original post here:
Remove array element from ALL documents using MongoDB C# driver
$[] operator selects all nested array ..You can update all array items with '$[]'
.update({"events.profile":10},{$set:{"events.$[].handled":0}},false,true)
Reference
Please be aware that some answers in this thread suggesting use $[] is WRONG.
db.collection.update(
{"events.profile":10},
{$set:{"events.$[].handled":0}},
{multi:true}
)
The above code will update "handled" to 0 for all elements in "events" array, regardless of its "profile" value. The query {"events.profile":10} is only to filter the whole document, not the documents in the array. In this situation it is a must to use $[elem] with arrayFilters to specify the condition of array items so Neil Lunn's answer is correct.
Actually, The save command is only on instance of Document class.
That have a lot of methods and attribute. So you can use lean() function to reduce work load.
Refer here. https://hashnode.com/post/why-are-mongoose-mongodb-odm-lean-queries-faster-than-normal-queries-cillvawhq0062kj53asxoyn7j
Another problem with save function, that will make conflict data in with multi-save at a same time.
Model.Update will make data consistently.
So to update multi items in array of document. Use your familiar programming language and try something like this, I use mongoose in that:
User.findOne({'_id': '4d2d8deff4e6c1d71fc29a07'}).lean().exec()
.then(usr =>{
if(!usr) return
usr.events.forEach( e => {
if(e && e.profile==10 ) e.handled = 0
})
User.findOneAndUpdate(
{'_id': '4d2d8deff4e6c1d71fc29a07'},
{$set: {events: usr.events}},
{new: true}
).lean().exec().then(updatedUsr => console.log(updatedUsr))
})
Update array field in multiple documents in mongo db.
Use $pull or $push with update many query to update array elements in mongoDb.
Notification.updateMany(
{ "_id": { $in: req.body.notificationIds } },
{
$pull: { "receiversId": req.body.userId }
}, function (err) {
if (err) {
res.status(500).json({ "msg": err });
} else {
res.status(200).json({
"msg": "Notification Deleted Successfully."
});
}
});
if you want to update array inside array
await Booking.updateOne(
{
userId: req.currentUser?.id,
cart: {
$elemMatch: {
id: cartId,
date: date,
//timeSlots: {
//$elemMatch: {
//id: timeSlotId,
//},
//},
},
},
},
{
$set: {
version: booking.version + 1,
'cart.$[i].timeSlots.$[j].spots': spots,
},
},
{
arrayFilters: [
{
'i.id': cartId,
},
{
'j.id': timeSlotId,
},
],
new: true,
}
);
I tried the following and its working fine.
.update({'events.profile': 10}, { '$set': {'events.$.handled': 0 }},{ safe: true, multi:true }, callback function);
// callback function in case of nodejs

Why can't I update all matching fields in a document with mongodb? [duplicate]

I have a Mongo document which holds an array of elements.
I'd like to reset the .handled attribute of all objects in the array where .profile = XX.
The document is in the following form:
{
"_id": ObjectId("4d2d8deff4e6c1d71fc29a07"),
"user_id": "714638ba-2e08-2168-2b99-00002f3d43c0",
"events": [{
"handled": 1,
"profile": 10,
"data": "....."
} {
"handled": 1,
"profile": 10,
"data": "....."
} {
"handled": 1,
"profile": 20,
"data": "....."
}
...
]
}
so, I tried the following:
.update({"events.profile":10},{$set:{"events.$.handled":0}},false,true)
However it updates only the first matched array element in each document. (That's the defined behaviour for $ - the positional operator.)
How can I update all matched array elements?
With the release of MongoDB 3.6 ( and available in the development branch from MongoDB 3.5.12 ) you can now update multiple array elements in a single request.
This uses the filtered positional $[<identifier>] update operator syntax introduced in this version:
db.collection.update(
{ "events.profile":10 },
{ "$set": { "events.$[elem].handled": 0 } },
{ "arrayFilters": [{ "elem.profile": 10 }], "multi": true }
)
The "arrayFilters" as passed to the options for .update() or even
.updateOne(), .updateMany(), .findOneAndUpdate() or .bulkWrite() method specifies the conditions to match on the identifier given in the update statement. Any elements that match the condition given will be updated.
Noting that the "multi" as given in the context of the question was used in the expectation that this would "update multiple elements" but this was not and still is not the case. It's usage here applies to "multiple documents" as has always been the case or now otherwise specified as the mandatory setting of .updateMany() in modern API versions.
NOTE Somewhat ironically, since this is specified in the "options" argument for .update() and like methods, the syntax is generally compatible with all recent release driver versions.
However this is not true of the mongo shell, since the way the method is implemented there ( "ironically for backward compatibility" ) the arrayFilters argument is not recognized and removed by an internal method that parses the options in order to deliver "backward compatibility" with prior MongoDB server versions and a "legacy" .update() API call syntax.
So if you want to use the command in the mongo shell or other "shell based" products ( notably Robo 3T ) you need a latest version from either the development branch or production release as of 3.6 or greater.
See also positional all $[] which also updates "multiple array elements" but without applying to specified conditions and applies to all elements in the array where that is the desired action.
Also see Updating a Nested Array with MongoDB for how these new positional operators apply to "nested" array structures, where "arrays are within other arrays".
IMPORTANT - Upgraded installations from previous versions "may" have not enabled MongoDB features, which can also cause statements to fail. You should ensure your upgrade procedure is complete with details such as index upgrades and then run
db.adminCommand( { setFeatureCompatibilityVersion: "3.6" } )
Or higher version as is applicable to your installed version. i.e "4.0" for version 4 and onwards at present. This enabled such features as the new positional update operators and others. You can also check with:
db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
To return the current setting
UPDATE:
As of Mongo version 3.6, this answer is no longer valid as the mentioned issue was fixed and there are ways to achieve this. Please check other answers.
At this moment it is not possible to use the positional operator to update all items in an array. See JIRA http://jira.mongodb.org/browse/SERVER-1243
As a work around you can:
Update each item individually
(events.0.handled events.1.handled
...) or...
Read the document, do the edits
manually and save it replacing the
older one (check "Update if
Current" if you want to ensure
atomic updates)
What worked for me was this:
db.collection.find({ _id: ObjectId('4d2d8deff4e6c1d71fc29a07') })
.forEach(function (doc) {
doc.events.forEach(function (event) {
if (event.profile === 10) {
event.handled=0;
}
});
db.collection.save(doc);
});
I think it's clearer for mongo newbies and anyone familiar with JQuery & friends.
This can also be accomplished with a while loop which checks to see if any documents remain that still have subdocuments that have not been updated. This method preserves the atomicity of your updates (which many of the other solutions here do not).
var query = {
events: {
$elemMatch: {
profile: 10,
handled: { $ne: 0 }
}
}
};
while (db.yourCollection.find(query).count() > 0) {
db.yourCollection.update(
query,
{ $set: { "events.$.handled": 0 } },
{ multi: true }
);
}
The number of times the loop is executed will equal the maximum number of times subdocuments with profile equal to 10 and handled not equal to 0 occur in any of the documents in your collection. So if you have 100 documents in your collection and one of them has three subdocuments that match query and all the other documents have fewer matching subdocuments, the loop will execute three times.
This method avoids the danger of clobbering other data that may be updated by another process while this script executes. It also minimizes the amount of data being transferred between client and server.
This does in fact relate to the long standing issue at http://jira.mongodb.org/browse/SERVER-1243 where there are in fact a number of challenges to a clear syntax that supports "all cases" where mutiple array matches are found. There are in fact methods already in place that "aid" in solutions to this problem, such as Bulk Operations which have been implemented after this original post.
It is still not possible to update more than a single matched array element in a single update statement, so even with a "multi" update all you will ever be able to update is just one mathed element in the array for each document in that single statement.
The best possible solution at present is to find and loop all matched documents and process Bulk updates which will at least allow many operations to be sent in a single request with a singular response. You can optionally use .aggregate() to reduce the array content returned in the search result to just those that match the conditions for the update selection:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$project": {
"events": {
"$setDifference": [
{ "$map": {
"input": "$events",
"as": "event",
"in": {
"$cond": [
{ "$eq": [ "$$event.handled", 1 ] },
"$$el",
false
]
}
}},
[false]
]
}
}}
]).forEach(function(doc) {
doc.events.forEach(function(event) {
bulk.find({ "_id": doc._id, "events.handled": 1 }).updateOne({
"$set": { "events.$.handled": 0 }
});
count++;
if ( count % 1000 == 0 ) {
bulk.execute();
bulk = db.collection.initializeOrderedBulkOp();
}
});
});
if ( count % 1000 != 0 )
bulk.execute();
The .aggregate() portion there will work when there is a "unique" identifier for the array or all content for each element forms a "unique" element itself. This is due to the "set" operator in $setDifference used to filter any false values returned from the $map operation used to process the array for matches.
If your array content does not have unique elements you can try an alternate approach with $redact:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$redact": {
"$cond": {
"if": {
"$eq": [ { "$ifNull": [ "$handled", 1 ] }, 1 ]
},
"then": "$$DESCEND",
"else": "$$PRUNE"
}
}}
])
Where it's limitation is that if "handled" was in fact a field meant to be present at other document levels then you are likely going to get unexepected results, but is fine where that field appears only in one document position and is an equality match.
Future releases ( post 3.1 MongoDB ) as of writing will have a $filter operation that is simpler:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$project": {
"events": {
"$filter": {
"input": "$events",
"as": "event",
"cond": { "$eq": [ "$$event.handled", 1 ] }
}
}
}}
])
And all releases that support .aggregate() can use the following approach with $unwind, but the usage of that operator makes it the least efficient approach due to the array expansion in the pipeline:
db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$unwind": "$events" },
{ "$match": { "events.handled": 1 } },
{ "$group": {
"_id": "$_id",
"events": { "$push": "$events" }
}}
])
In all cases where the MongoDB version supports a "cursor" from aggregate output, then this is just a matter of choosing an approach and iterating the results with the same block of code shown to process the Bulk update statements. Bulk Operations and "cursors" from aggregate output are introduced in the same version ( MongoDB 2.6 ) and therefore usually work hand in hand for processing.
In even earlier versions then it is probably best to just use .find() to return the cursor, and filter out the execution of statements to just the number of times the array element is matched for the .update() iterations:
db.collection.find({ "events.handled": 1 }).forEach(function(doc){
doc.events.filter(function(event){ return event.handled == 1 }).forEach(function(event){
db.collection.update({ "_id": doc._id },{ "$set": { "events.$.handled": 0 }});
});
});
If you are aboslutely determined to do "multi" updates or deem that to be ultimately more efficient than processing multiple updates for each matched document, then you can always determine the maximum number of possible array matches and just execute a "multi" update that many times, until basically there are no more documents to update.
A valid approach for MongoDB 2.4 and 2.2 versions could also use .aggregate() to find this value:
var result = db.collection.aggregate([
{ "$match": { "events.handled": 1 } },
{ "$unwind": "$events" },
{ "$match": { "events.handled": 1 } },
{ "$group": {
"_id": "$_id",
"count": { "$sum": 1 }
}},
{ "$group": {
"_id": null,
"count": { "$max": "$count" }
}}
]);
var max = result.result[0].count;
while ( max-- ) {
db.collection.update({ "events.handled": 1},{ "$set": { "events.$.handled": 0 }},{ "multi": true })
}
Whatever the case, there are certain things you do not want to do within the update:
Do not "one shot" update the array: Where if you think it might be more efficient to update the whole array content in code and then just $set the whole array in each document. This might seem faster to process, but there is no guarantee that the array content has not changed since it was read and the update is performed. Though $set is still an atomic operator, it will only update the array with what it "thinks" is the correct data, and thus is likely to overwrite any changes occurring between read and write.
Do not calculate index values to update: Where similar to the "one shot" approach you just work out that position 0 and position 2 ( and so on ) are the elements to update and code these in with and eventual statement like:
{ "$set": {
"events.0.handled": 0,
"events.2.handled": 0
}}
Again the problem here is the "presumption" that those index values found when the document was read are the same index values in th array at the time of update. If new items are added to the array in a way that changes the order then those positions are not longer valid and the wrong items are in fact updated.
So until there is a reasonable syntax determined for allowing multiple matched array elements to be processed in single update statement then the basic approach is to either update each matched array element in an indvidual statement ( ideally in Bulk ) or essentially work out the maximum array elements to update or keep updating until no more modified results are returned. At any rate, you should "always" be processing positional $ updates on the matched array element, even if that is only updating one element per statement.
Bulk Operations are in fact the "generalized" solution to processing any operations that work out to be "multiple operations", and since there are more applications for this than merely updating mutiple array elements with the same value, then it has of course been implemented already, and it is presently the best approach to solve this problem.
First: your code did not work because you were using the positional operator $ which only identifies an element to update in an array but does not even explicitly specify its position in the array.
What you need is the filtered positional operator $[<identifier>]. It would update all elements that match an array filter condition.
Solution:
db.collection.update({"events.profile":10}, { $set: { "events.$[elem].handled" : 0 } },
{
multi: true,
arrayFilters: [ { "elem.profile": 10 } ]
})
Visit mongodb doc here
What the code does:
{"events.profile":10} filters your collection and return the documents matching the filter
The $set update operator: modifies matching fields of documents it acts on.
{multi:true} It makes .update() modifies all documents matching the filter hence behaving like updateMany()
{ "events.$[elem].handled" : 0 } and arrayFilters: [ { "elem.profile": 10 } ]
This technique involves the use of the filtered positional array with arrayFilters. the filtered positional array here $[elem] acts as a placeholder for all elements in the array fields that match the conditions specified in the array filter.
Array filters
You can update all elements in MongoDB
db.collectioname.updateOne(
{ "key": /vikas/i },
{ $set: {
"arr.$[].status" : "completed"
} }
)
It will update all the "status" value to "completed" in the "arr" Array
If Only one document
db.collectioname.updateOne(
 { key:"someunique", "arr.key": "myuniq" },
 { $set: {
   "arr.$.status" : "completed",
   "arr.$.msgs":  {
        "result" : ""
        }
   
 } }
)
But if not one and also you don't want all the documents in the array to update then you need to loop through the element and inside the if block
db.collectioname.find({findCriteria })
.forEach(function (doc) {
doc.arr.forEach(function (singlearr) {
if (singlearr check) {
singlearr.handled =0
}
});
db.collection.save(doc);
});
I'm amazed this still hasn't been addressed in mongo. Overall mongo doesn't seem to be great when dealing with sub-arrays. You can't count sub-arrays simply for example.
I used Javier's first solution. Read the array into events then loop through and build the set exp:
var set = {}, i, l;
for(i=0,l=events.length;i<l;i++) {
if(events[i].profile == 10) {
set['events.' + i + '.handled'] = 0;
}
}
.update(objId, {$set:set});
This can be abstracted into a function using a callback for the conditional test
The thread is very old, but I came looking for answer here hence providing new solution.
With MongoDB version 3.6+, it is now possible to use the positional operator to update all items in an array. See official documentation here.
Following query would work for the question asked here. I have also verified with Java-MongoDB driver and it works successfully.
.update( // or updateMany directly, removing the flag for 'multi'
{"events.profile":10},
{$set:{"events.$[].handled":0}}, // notice the empty brackets after '$' opearor
false,
true
)
Hope this helps someone like me.
I've been looking for a solution to this using the newest driver for C# 3.6 and here's the fix I eventually settled on. The key here is using "$[]" which according to MongoDB is new as of version 3.6. See https://docs.mongodb.com/manual/reference/operator/update/positional-all/#up.S[] for more information.
Here's the code:
{
var filter = Builders<Scene>.Filter.Where(i => i.ID != null);
var update = Builders<Scene>.Update.Unset("area.$[].discoveredBy");
var result = collection.UpdateMany(filter, update, new UpdateOptions { IsUpsert = true});
}
For more context see my original post here:
Remove array element from ALL documents using MongoDB C# driver
$[] operator selects all nested array ..You can update all array items with '$[]'
.update({"events.profile":10},{$set:{"events.$[].handled":0}},false,true)
Reference
Please be aware that some answers in this thread suggesting use $[] is WRONG.
db.collection.update(
{"events.profile":10},
{$set:{"events.$[].handled":0}},
{multi:true}
)
The above code will update "handled" to 0 for all elements in "events" array, regardless of its "profile" value. The query {"events.profile":10} is only to filter the whole document, not the documents in the array. In this situation it is a must to use $[elem] with arrayFilters to specify the condition of array items so Neil Lunn's answer is correct.
Actually, The save command is only on instance of Document class.
That have a lot of methods and attribute. So you can use lean() function to reduce work load.
Refer here. https://hashnode.com/post/why-are-mongoose-mongodb-odm-lean-queries-faster-than-normal-queries-cillvawhq0062kj53asxoyn7j
Another problem with save function, that will make conflict data in with multi-save at a same time.
Model.Update will make data consistently.
So to update multi items in array of document. Use your familiar programming language and try something like this, I use mongoose in that:
User.findOne({'_id': '4d2d8deff4e6c1d71fc29a07'}).lean().exec()
.then(usr =>{
if(!usr) return
usr.events.forEach( e => {
if(e && e.profile==10 ) e.handled = 0
})
User.findOneAndUpdate(
{'_id': '4d2d8deff4e6c1d71fc29a07'},
{$set: {events: usr.events}},
{new: true}
).lean().exec().then(updatedUsr => console.log(updatedUsr))
})
Update array field in multiple documents in mongo db.
Use $pull or $push with update many query to update array elements in mongoDb.
Notification.updateMany(
{ "_id": { $in: req.body.notificationIds } },
{
$pull: { "receiversId": req.body.userId }
}, function (err) {
if (err) {
res.status(500).json({ "msg": err });
} else {
res.status(200).json({
"msg": "Notification Deleted Successfully."
});
}
});
if you want to update array inside array
await Booking.updateOne(
{
userId: req.currentUser?.id,
cart: {
$elemMatch: {
id: cartId,
date: date,
//timeSlots: {
//$elemMatch: {
//id: timeSlotId,
//},
//},
},
},
},
{
$set: {
version: booking.version + 1,
'cart.$[i].timeSlots.$[j].spots': spots,
},
},
{
arrayFilters: [
{
'i.id': cartId,
},
{
'j.id': timeSlotId,
},
],
new: true,
}
);
I tried the following and its working fine.
.update({'events.profile': 10}, { '$set': {'events.$.handled': 0 }},{ safe: true, multi:true }, callback function);
// callback function in case of nodejs

MongoDB findAndModify not working with monk

I am trying to use findAndModify with the node.js mongodb module monk.This is the method that I am using,this throws a 500 error in my cmd:
notesCollection.findAndModify({_id:_id},[],{_id:_id,title:title,content:content},{'new':true,'upsert':true},function(err,doc){
if(err)
console.error(err);
else
{
console.log("Find and modify successfull");
console.dir(doc);
}
});
I obtained the method signature here.I get an error that looks like this and is uninformative:
POST /notes/edit/542bdec5712c0dc426d41342 500 86ms - 1.35kb
Monk implements methods that are more in line with the shell syntax for method signatures than what is provided by the node native driver. So in this case the "shell" documentation for .findAndModify() is more appropriate for here:
notescollection.findAndModify(
{
"query": { "_id": id },
"update": { "$set": {
"title": title,
"content": content
}},
"options": { "new": true, "upsert": true }
},
function(err,doc) {
if (err) throw err;
console.log( doc );
}
);
Also noting that you should be using the $set operator or posibly even the $setOnInsert operator where you only want fields applied when the document is created. When operators like this a re not applied then the "whole" document is replaced with whatever content you specify for the "update".
You also don't need to supply the "_id" field in the update section, as even when an "upsert" occurs, anything present in the "query" portion of the statement is implied to be created in a new document.
The monk documentation also hints at the correct syntax to use for the method signature.
Had the same problem, and even though I liked it, the accepted answer didn't work for me.
It's not clear enough, but the documentation hints at the correct syntax, starting with the signatures:
All commands accept the simple data[, …], fn. For example
findAndModify({}, {}, fn)
And from the finding section:
users.findAndModify({ _id: '' }, { $set: {} });
Finally, continuing with the signatures section:
You can pass options in the middle: data[, …], options, fn
Putting it all together:
collection.findAndModify({
_id: '',
}, {
$set: {
value: '',
},
}, {
upsert: true,
});
So in this case, data[, …] is the couple {}, {} objects: query and update. Then you can add the callback as a 4th parameter in my snippet.

How to find all elements of a collection in an array that matches two conditions

I've been looking at this documentation, and I tried to implement it here:
customers.find({'name':tenantName,'scripts.author':author},'scripts',function(err,data2){
But this doesn't find what I want it to find. and I get back every element of scripts whether scripts.author matches or not.
What am I doing wrong?
My data looks like this
{
name: "something"
scripts:[
{author:"something", data:"data"},
{author:"something else" data:"data2"},
{author:"something", data:"data3"}
]
}
I'd like to get all the scripts where author matches what I give it
There are a few things wrong here for you to understand about matching in queries like this. First of all, what your were trying to do was this:
customer.find(
{ "name":tenantName, "scripts.author": author },
{ "scripts.$" },
function(err,data2) {
// work here
})
And that would use the positional $ operator to match the element. But the problem here is that will only match the first element of the array. This is covered in the documentation. The result will be like this:
{ "scripts" : [ { "author" : "something", "data" : "data" } ] }
If you need to match muliple elements, then you need to use the aggregate function in order to filter the array contents:
customer.aggregate([
// Match just the documents you want
{ "$match": { "name": tenantName, "scripts.author": author } },
// Unwind the array
{ "$unwind": "$scripts" },
// Match to filter just the array elements
{ "$match": { "scripts.author": author } },
// Push back the array elements
{ "$group": {
"_id": "$_id",
"name": { "$first": "$name" },
"scripts": { "$push": "$scripts" }
}}
],
function(err,result) {
})
And the results there will be the two elements that match "something" as the author.
Why all of this? Well there is the limitation on what can be done with projection that was mentioned. But the main reason is that you are not matching elements in the array, but you are matching the document that "contains" the matching elements in the array.
So if you really want to filter the results, this is how you do it.

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