In the document below, I have an array called imAccounts. I want to update() the object in that array. How can I do that?
{
"_id" : ObjectId("503c55da1c192a530b000001"),
"imAccounts" : [
{
"accountType" : "Windows",
"accountName" : "rwqerqw",
"accountPassword" : "erqwerwe"
},
{
"accountType" : "Yahoo",
"accountName" : "rwqerqw",
"accountPassword" : "erqwerwe"
}]
}
With this document structure you can update an object in the array using the positional operator ($):
db.myarray.update(
{ // Match criteria
"_id" : ObjectId("503c55da1c192a530b000001"),
'imAccounts.accountType': 'Yahoo',
},
{ // Update first matched item using positional operator $
'$set' : { 'imAccounts.$.password':'sekrit'}
}
)
Note that the positional operator currently only applies to the first matched item in the query.
Related
Here is my news document structure
{
"_id" : ObjectId("5bff0903bd9a221229c7c9b2"),
"title" : "Test Page",
"desc" : "efdfr",
"mediaset_list" : [
{
"_id" : ObjectId("5bfeff94bd9a221229c7c9ae"),
"medias" : [
{
"_id" : ObjectId("5bfeff83bd9a221229c7c9ac"),
"file_type" : "png",
"file" : "https://aws.com/gg.jpg",
"file_name" : "edf.jpg"
},
{
"_id" : ObjectId("5bfeff83bd9a221229c7c9ad"),
"file_type" : "mov",
"file" : "https://aws.com/gg.mov",
"file_name" : "abcd.mov"
}
]
}
]}
The queries that i've tried are given below
Approach 1
db.news.find_and_modify({},{'$pull': {"mediaset_list": {"medias": {"$elemMatch" : {"_id": ObjectId('5bfeff83bd9a221229c7c9ac')}} }}})
Approach 2
db.news.update({},{'$pull': {"mediaset_list.$.medias": {"_id": ObjectId('5bfeff83bd9a221229c7c9ac')}} })
Issue we are facing
The above queries are removing entire elements inside 'mediaset_list' . But i only want to remove the element inside 'medias' matching object ID.
Since you have two nested arrays you have to use arrayFilters to indicate which element of outer array should be modified, try:
db.news.update({ _id: ObjectId("5bff0903bd9a221229c7c9b2") },
{ $pull: { "mediaset_list.$[item].medias": { _id: ObjectId("5bfeff83bd9a221229c7c9ad") } } },
{ arrayFilters: [ { "item._id": ObjectId("5bfeff94bd9a221229c7c9ae") } ] })
So item is used here as a placeholder which will be used by MongoDB to determine which element of mediaset_list needs to be modified and the condition for this placeholder is defined inside arrayFilters. Then you can use $pull and specify another condition for inner array to determine which element should be removed.
From #micki's mongo shell query (Answer above) , This is the pymongo syntax which will update all news document with that media id .
db.news.update_many({},
{
"$pull":
{ "mediaset_list.$[item].medias": { "_id": ObjectId("5bfeff83bd9a221229c7c9ad") } } ,
},
array_filters=[{ "item._id": ObjectId("5bfeff94bd9a221229c7c9ae")}],
upsert=True)
I have a document in Mongodb collection, where I want to remove an object, using title key.
I tried using $unset, but it only removes the title key not the object to which it belongs.
{
"_id" : ObjectId("576b63d49d20504c1360f688"),
"books" : [
{
"art_id" : ObjectId("574e68e5ac9fbac82489b689"),
"title" :"abc",
"price" : 40
},
{
"art_id" : ObjectId("575f9badada0500d192c53f4"),
"title" : "xyz",
"price" : 20
},
{
"art_id" : ObjectId("57458224d86b3d1561150f17"),
"title" : "def",,
"price" : 30
}
],
"user_id" : "575570c315e27d13167dfc0d"
}
To remove the entire object that contains the query object use db.remove() query.
For your case:
db.yourcollection.remove({"books.title": "abc"});
Please double check the format in which the element of array is referenced.
This removes the entire objects that contains the embedded query obj. To remove only a single object, provide it with another field to uniquely identify it.
If you only want to remove the object that contains the title field from the array but wants to keep the object that contains the array, then please use the $pull operator. This answer will be of help.
Example: if you want to remove object
{
"art_id" : ObjectId("574e68e5ac9fbac82489b689"),
"title" :"abc",
"price" : 40
}
just from the array but keep the parent object like
{
"_id" : ObjectId("576b63d49d20504c1360f688"),
"books" : [
{
"art_id" : ObjectId("575f9badada0500d192c53f4"),
"title" : "xyz",
"price" : 20
},
{
"art_id" : ObjectId("57458224d86b3d1561150f17"),
"title" : "def",,
"price" : 30
}
],
"user_id" : "575570c315e27d13167dfc0d"
}
use
db.mycollection.update(
{'_id': ObjectId("576b63d49d20504c1360f688")},
{ $pull: { "books" : { "title": "abc" } } },
false,
true
);
$unset won't remove the object from an array. The $unset operator deletes a particular field. doc.
Use $pull instead.
The $pull operator removes from an existing array all instances of a value or values that match a specified condition.
Try following query
db.collName.update({$pull : {books:{title:abc}}})
Refer $pull-doc
Hope this will help you.
And if... ¿Do I want to delete an object that is inside a document and not as an array?
{
"_id" : ObjectId("576b63d49d20504c1360f688"),
"books" : {
"574e68e5ac9fbac82489b689": {
"art_id" : ObjectId("574e68e5ac9fbac82489b689"),
"title" :"abc",
"price" : 40
},
"575f9badada0500d192c53f4": {
"art_id" : ObjectId("575f9badada0500d192c53f4"),
"title" :"xyz",
"price" : 20
},
"57458224d86b3d1561150f17": {
"art_id" : ObjectId("57458224d86b3d1561150f17"),
"title" : "def",
"price" : 30
}
},
"user_id" : "575570c315e27d13167dfc0d"
}
The solutions is this:
db.auctions.update(
{'_id': ObjectId("576b63d49d20504c1360f688")},
{$unset: {"books.574e68e5ac9fbac82489b689":
{_id: "574e68e5ac9fbac82489b689"}}})
Try using pull.
https://docs.mongodb.com/manual/reference/operator/update/pull/
$pull
The $pull operator removes from an existing array all instances of a value or values that match a specified condition.
The $pull operator has the form:
{ $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } }
To specify a <field> in an embedded document or in an array, use dot notation.
Try in the mongo shell
db.yourcollection.remove({books:[{title:'title_you_want'}]})
Careful with the braces.
I have a document as follows:
{
"_id" : ObjectId("56423b2558cb340599108b35"),
"test" : {
"source" : [
{
"member" : "abc"
},
{
"member" : "xyz"
}
]
}
}
I want to filter on the array element xyz, and I am trying the following query:
db.coll.find({ "test.source.member" : "xyz" }, { "test.source.$.member" : true }).pretty()
Apparently it used to work on 2.4, on 2.6 it does not work,
On 2.4 it returned the "xyz", whereas on 2.6 it returns "abc" i.e. the first element. Is there a way to filter "abc" because eventually i want to update. BTW, i also tried with $elemMatch and it seems to give the same output "abc".
Thanks.
According to the Docs, if you are running 2.6, this should give you the correct output:
db.coll.find({ "test.source.member" : "xyz"}, { "test.source.$" : 1}).pretty()
You could extract the member by doing this:
var member = db.coll.find(
{ "test.source.member" : "xyz"},
{ "test.source.$" : 1}
).test.source[0].member;
The value of member would be:
xyz
here is a typical document
{
title : 'someTitle',
places : [{name : 'someName', location : 'someLocation'}, {name ...}]
}
I have the following query
var qs = {title : 'someTitle', places : {$elemMatch : {name : 'someName' } } };
where I select a document which matches the title and which contains a document entry within its 'places' array that has name equal to 'someName'. However the issue is that the entries within the places array are large documents, and I only need a couple of fields from that document. I tried projecting the fields like so but it did not work.
var projection = {'places.$.name': 1, 'places.$.location' : 1};
Which is supposed to return an array with a document containing only the 'name' and 'location' property.
I got the following error
Can't canonicalize query: BadValue Cannot specify more than one positional proj. per query.
to be clear, I would like to accomplish this without the aggregate framework
You are doing it wrong. According to the documentation
Only one positional $ operator may appear in the projection document.
But you still need to use the $ operator to get the expected result:
var qs = { title : 'someTitle', 'places.name' : 'someName' };
var projection = {'places.$': 1 };
db.collection.find(qs, projection);
Which returns:
{
"_id" : ObjectId("564f52d7d9a433df958b5630"),
"places" : [
{
"name" : "someName",
"location" : "someLocation"
}
]
}
Also you don't need the $elemMatch operator here use "dot notation" instead.
Now if what you want is an array of "name" and "location" for each subdocument in the array then aggregation is the way to go.
db.collection.aggregate([
{ '$match': {
'title' : 'someTitle',
'places.name' : 'someName'
}},
{ '$project': {
'places': {
'$map': {
'input': '$places',
'as': 'place',
'in': {
'name': '$$place.name',
'location': '$$place.location'
}
}
}
}}
])
Which yields:
{
"_id" : ObjectId("564f52d7d9a433df958b5630"),
"places" : [
{
"name" : "someName",
"location" : "someLocation"
},
{
"name" : "bar",
"location" : "foo"
}
]
}
For the fields inside an array, you can project them the same as in embedded object
var projection = {'places.name': 1, 'places.location' : 1};
Check this guideline
https://docs.mongodb.com/manual/reference/operator/aggregation/project/#include-specific-fields-from-embedded-documents
/* 0 */
{
"_id" : ObjectId("55addc2f8dab32aca87ce0bd"),
"partNum" : "part1",
"dest" : "First Part",
"sales" : [
"sale1",
"sale2",
"sale3"
],
"salesData" : {
"sale1" : {
"mcode" : "mc11",
"dtype" : [
"AAA",
"BBB"
]
}
}
}
/* 1 */
{
"_id" : ObjectId("55addc408dab32aca87ce0be"),
"partNum" : "part2",
"dest" : "Second Part",
"sales" : [
"sale1",
"sale2",
"sale3"
],
"salesData" : {
"sale1" : {
"mcode" : "mc22",
"dtype" : [
"AAA",
"BBB"
]
}
}
}
I am not that much efficient in writing mongo script. My requirement is to append one more value to "dtype" array wherever "mcode" is "mc11" in all of the documents inside the collection. Above is the two document output from my collection. I was using the below script to do it and its not working. Can anyone please help me
db.testingRD.find().forEach( function(myDocument)
{
db.testingRD.update({id: myDocument._id}, {$push : {"salesData.sale1.dtype" : "DDD"}});
});
To append one more value to "dtype" array wherever "mcode" is "mc11", use the following update where the query object is the selection criteria for the update and is the same query selector as in the find() method, the update object has the $push modifications to apply and then the options document which is optional. If that is set to true, it updates multiple documents that meet the query criteria:
var query = { "salesData.sale1.mcode": "mc11" },
update = {
"$push": { "salesData.sale1.dtype": "DDD" }
},
options = { "multi": true };
db.testingRD.update(query, update, options);
You had a typing mistake in the script (you forgot an underscore):
db.testingRD.find().forEach( function(myDocument)
{
db.testingRD.update({_id: myDocument._id}, {$push : {"salesData.sale1.dtype" : "DDD"}});
});
I always use a trick when an update seams to not working: I change the update with a printjson + find so that I can see if it is matching anything:
db.testingRD.find().forEach( function(myDocument) { printjson(db.testingRD.find({_id: myDocument._id})) } );