I'm having a (hopefully) small syntax problem with $pull in Mongodb.
bulk.find({_id: new mongo.ObjectID(req.session._id)}).updateOne({$pull: {
firstArray: {id: req.params.id},
'secondArray.firstArrayIds': req.params.id
'secondArray.$.firstArrayIds': req.params.id
}});
The firstArray $pull works just fine.
But the secondArray.firstArrayIds and/or secondArray.$.firstArrayIds does not. What am I doing wrong here?
This is my data structure:
clients: {
firstArray: [
{
_id: '153'.
someField1: 'someVal1',
}
...
]
secondArray: [
{
_id: '7423'.
someField1: 'someVal1',
firstArrayIds: [153, 154, 155, ...]
}
...
]
}
EDIT What if there are more than one embedded object in secondArray which firstArrayIds can contain the id i want to delete. In other words, when deleting an object in firstdArray i want to delete references in all secondArray's firstArrayIds Not just the first match.
Your "secondArray" has a nested element structure, so you must identify the outer element you want to match in your query when using a positional $ operator in the update. You basically need something like this:
bulk.find({
"_id": new mongo.ObjectID(req.session._id),
"secondArray._id": "7423"
}).update({
"$pull": {
"firstArray": { "_id": "153" },
"secondArray.$.firstArrayIds": 153
}
});
So there are in fact "two" id values you need to pass in with your request in addition to the general document id. Even though this is nested it is okay since you are only matching on the "outer" level and only on one array. If you tried to match the position on more than one array then this is not possible with the positional operator.
Related
I am trying to $pull a certain document contained within a nested array, within another nested array.
The structure goes as follows:
*clubs{ "club_id",
"players"[{"player_id": 123,
"comments": [{"_id": "id"},
{"_id": "id2"}]
}]
}
I am trying to use the below in mongosh:
db.clubs.updateOne({"players.player_id": 363205}, {$pull: {"players.comments": {"players.comments._id": "5c61f001-768c-11ed-892f-346f24b28bd0"}}})
But when I submit this I get the following error:
MongoServerError: Cannot use the part (comments) of (players.comments) to traverse the element ({players: ...
Can someone please lend a hand here and let me know where I am going wrong? I've had a similar query work earlier, however it was only on 1 nested array of documents, rather than a nested array in a document that itself is contained in a nested array. Thanks in advance! :)
Update with $[<identifier>] filtered positional operator.
db.clubs.updateOne({
"players.player_id": 363205
},
{
$pull: {
"players.$[player].comments": {
"_id": "5c61f001-768c-11ed-892f-346f24b28bd0"
}
}
},
{
arrayFilters: [
{
"player.player_id": 363205
}
]
})
Demo # Mongo Playground
I want to filter my collection by aggregation for one of many ObjectIDs.
Because of some DocumentDB restrictions I can not build a single pipeline with uncorrelated subqueries. So my fix is to do it in two queries.
for example: I have an aggregation that returns all teamIds, for some conditions as an array of Object with the IDs.
[{_id: ObjectID("abcdef")}, {_id: ObjectID("ghijkl")}, {_id: ObjectID("vwxyz")}, ...]
I now want to have a second aggregation filter another collection using the ObjectIDs.
This would work in Mongo Compass:
{
"team": {
"$in": [ObjectId("60aabcb05c7462f42b3d7zyx"), ObjectId("60aabc7b05c7462f42b3dxyz")]
},
....
}
My issue is that i can not find the correct syntax for JS to generate such a pipeline.
What ever I try, JS always converts my Array of ObjectIDs to something like this:
{
"team": {
"$in": [{
"_id": "60aabcb05c7462f42b3d7zyx"
},{
"_id": "60aabc7b05c7462f42b3dxyz"
}]
},
I fixed it like this. I am not 100% why this syntax works because it is still just an array of objects, formatted like before, but I guess there is some stuff mongoose does, that is opaque to me.
let teams = await TeamMgmt.getTeamsAggregatedByFilter( teamFilter )
// make an array of ObjectIds so we can filter for them.
let idArray = []
Object.keys( teams ).map( function ( key, index ) {
idArray.push( new mongoose.Types.ObjectId( teams[ index ]._id.toString() ) )
} );
const shiftFilter = [
{
'$match': {
'team': {
"$in": idArray
},
....
}
This has been extensively covered here, but none of the solutions seems to be working for me. I'm attempting to remove an object from an array using that object's id. Currently, my Schema is:
const scheduleSchema = new Schema({
//unrelated
_id: ObjectId
shifts: [
{
_id: Types.ObjectId,
name: String,
shift_start: Date,
shift_end: Date,
},
],
});
I've tried almost every variation of something like this:
.findOneAndUpdate(
{ _id: req.params.id },
{
$pull: {
shifts: { _id: new Types.ObjectId(req.params.id) },
},
}
);
Database:
Database Format
Within these variations, the usual response I've gotten has been either an empty array or null.
I was able slightly find a way around this and accomplish the deletion by utilizing the main _id of the Schema (instead of the nested one:
.findOneAndUpdate(
{ _id: <main _id> },
{ $pull: { shifts: { _id: new Types.ObjectId(<nested _id>) } } },
{ new: true }
);
But I was hoping to figure out a way to do this by just using the nested _id. Any suggestions?
The problem you are having currently is you are using the same _id.
Using mongo, update method allows three objects: query, update and options.
query object is the object into collection which will be updated.
update is the action to do into the object (add, change value...).
options different options to add.
Then, assuming you have this collection:
[
{
"_id": 1,
"shifts": [
{
"_id": 2
},
{
"_id": 3
}
]
}
]
If you try to look for a document which _id is 2, obviously response will be empty (example).
Then, if none document has been found, none document will be updated.
What happens if we look for a document using shifts._id:2?
This tells mongo "search a document where shifts field has an object with _id equals to 2". This query works ok (example) but be careful, this returns the WHOLE document, not only the array which match the _id.
This not return:
[
{
"_id": 1,
"shifts": [
{
"_id": 2
}
]
}
]
Using this query mongo returns the ENTIRE document where exists a field called shifts that contains an object with an _id with value 2. This also include the whole array.
So, with tat, you know why find object works. Now adding this to an update query you can create the query:
This one to remove all shifts._id which are equal to 2.
db.collection.update({
"shifts._id": 2
},
{
$pull: {
shifts: {
_id: 2
}
}
})
Example
Or this one to remove shifts._id if parent _id is equal to 1
db.collection.update({
"_id": 1
},
{
$pull: {
shifts: {
_id: 2
}
}
})
Example
I have a mongodb collection.
{ user_id: 1,
items : [ { _id: 1 }, { _id: 2}, {_id:3} ] }
I want to remove the items of the array having specific id. Can anybody explain what is wrong with the above query.
db.col.findOneAndUpdate({user_id:1},{$pull:{items:{$elemMatch:{_id:2}}}})
$pull takes an expression as a parameter so you don't have to use $elemMatch (doesn't work in this case). Try:
db.col.update({user_id:1},{$pull:{items:{_id:2}}})
So expression in this case means that MongoDB will remove the document having _id set to 2 but that document can have other properties as well.
I have a collection which elements can be simplified to this:
{tags : [1, 5, 8]}
where there would be at least one element in array and all of them should be different. I want to substitute one tag for another and I thought that there would not be a problem. So I came up with the following query:
db.colll.update({
tags : 1
},{
$pull: { tags: 1 },
$addToSet: { tags: 2 }
}, {
multi: true
})
Cool, so it will find all elements which has a tag that I do not need (1), remove it and add another (2) if it is not there already. The problem is that I get an error:
"Cannot update 'tags' and 'tags' at the same time"
Which basically means that I can not do pull and addtoset at the same time. Is there any other way I can do this?
Of course I can memorize all the IDs of the elements and then remove tag and add in separate queries, but this does not sound nice.
The error is pretty much what it means as you cannot act on two things of the same "path" in the same update operation. The two operators you are using do not process sequentially as you might think they do.
You can do this with as "sequential" as you can possibly get with the "bulk" operations API or other form of "bulk" update though. Within reason of course, and also in reverse:
var bulk = db.coll.initializeOrderedBulkOp();
bulk.find({ "tags": 1 }).updateOne({ "$addToSet": { "tags": 2 } });
bulk.find({ "tags": 1 }).updateOne({ "$pull": { "tags": 1 } });
bulk.execute();
Not a guarantee that nothing else will try to modify,but it is as close as you will currently get.
Also see the raw "update" command with multiple documents.
If you're removing and adding at the same time, you may be modeling a 'map', instead of a 'set'. If so, an object may be less work than an array.
Instead of data as an array:
{ _id: 'myobjectwithdata',
data: [{ id: 'data1', important: 'stuff'},
{ id: 'data2', important: 'more'}]
}
Use data as an object:
{ _id: 'myobjectwithdata',
data: { data1: { important: 'stuff'},
data2: { important: 'more'} }
}
The one-command update is then:
db.coll.update(
'myobjectwithdata',
{ $set: { 'data.data1': { important: 'treasure' } }
);
Hard brain working for this answer done here and here.
Starting in Mongo 4.4, the $function aggregation operator allows applying a custom javascript function to implement behaviour not supported by the MongoDB Query Language.
And coupled with improvements made to db.collection.update() in Mongo 4.2 that can accept an aggregation pipeline, allowing the update of a field based on its own value,
We can manipulate and update an array in ways the language doesn't easily permit:
// { "tags" : [ 1, 5, 8 ] }
db.collection.updateMany(
{ tags: 1 },
[{ $set:
{ "tags":
{ $function: {
body: function(tags) { tags.push(2); return tags.filter(x => x != 1); },
args: ["$tags"],
lang: "js"
}}
}
}]
)
// { "tags" : [ 5, 8, 2 ] }
$function takes 3 parameters:
body, which is the function to apply, whose parameter is the array to modify. The function here simply consists in pushing 2 to the array and filtering out 1.
args, which contains the fields from the record that the body function takes as parameter. In our case, "$tag".
lang, which is the language in which the body function is written. Only js is currently available.
In case you need replace one value in an array to another check this answer:
Replace array value using arrayFilters