How to query all {"module" : "B"} ?
The following query doesn't work:
db.XXX.find({ "_id" : { "module" : "B" } });
Thanks a ton!
There data looks like:
{
"_id" : {"module" : "A","date" : ISODate("2013-03-18T07:00:00Z")},
"value" : {"count" : 1.0}
}
{
"_id" : {"module" : "B","date" : ISODate("2013-03-18T08:00:00Z")},
"value" : {"count" : 2.0}
}
Try:
db.XXX.find({ "_id.module" : "B" });
The difference is your original query would be trying to match on that entire subdocument (i.e. where _id is a subdocument containing a "module" field with value "B" and nothing else)
Reference: MongoDB Dot Notation
Use dot notation:
db.XXX.find({ "_id.module" : "B" })
For Exact match on Subdocument
db.bios.find(
{
'_id.module': 'B'
}
)
the query uses dot notation to access fields in a subdocument:
Refference link
Related
I did this in my mongodb:
db.teams.insert({name:"Alpha team",employees:[{name:"john"},{name:"david"}]});
db.teams.insert({name:"True team",employees:[{name:"oliver"},{name:"sam"}]});
db.teams.insert({name:"Blue team",employees:[{name:"jane"},{name:"raji"}]});
db.teams.find({"employees.name":/.*o.*/});
But what I got was:
{ "_id" : ObjectId("5ddf3ca83c182cc5354a15dd"), "name" : "Alpha team", "employees" : [ { "name" : "john" }, { "name" : "david" } ] }
{ "_id" : ObjectId("5ddf3ca93c182cc5354a15de"), "name" : "True team", "employees" : [ { "name" : "oliver" }, { "name" : "sam" } ] }
But what I really want is
[{"name":"john"},{"name":"oliver"}]
I'm having a hard time finding examples of this without using some kind of programmatic iterator/loop. Or examples I find return the parent document, which means I'd have to parse out the embedded array employees and do some kind of UNION statement?
Eg.
How to get embedded document in mongodb?
Retrieve only the queried element in an object array in MongoDB collection
Can someone point me in the right direction?
Please add projections to filter out the fields you don't need. Please refer the project link mongodb projections
Your find query should be constructed with the projection parameters like below:
db.teams.find({"employees.name":/.*o.*/}, {_id:0, "employees.name": 1});
This will return you:
[{"name":"john"},{"name":"oliver"}]
Can be solved with a simple aggregation pipeline.
db.teams.aggregate([
{$unwind : "$employees"},
{$match : {"employees.name":/.*o.*/}},
])
EDIT:
OP Wants to skip the parent fields. Modified query:
db.teams.aggregate([
{$unwind : "$employees"},
{$match : {"employees.name":/.*o.*/}},
{$project : {"name":"$employees.name",_id:0}}
])
Output:
{ "name" : "john" }
{ "name" : "oliver" }
In a find query projection, fields I specify after the positional operator are ignored and the whole document is always returned.
'myArray.$.myField' : 1 behave exactly like 'myArray.$' : 1
the positional operator selects the right document. But this document is quite big. I would like to project only 1 field from it.
Exemple:
db.getCollection('match').find({"participantsData.id" : 0001}, { 'participantsData.$.id': 1, })
here the response I have
{
"_id" : "myid",
"matchCreation" : 1463916465614,
"participantsData" : [
{
"id" : 0001,
"plenty" : "of",
"other" : "fields",
"and" : "subdocuments..."
}
]
}
This is what I want
{
"_id" : "myid",
"matchCreation" : 1463916465614,
"participantsData" : [
{
"id" : 0001
}
]
}
Is it possible with mongo?
Yes it can be done in mongo
Please try the below query
db.getCollection('match').find(
{"participantsData.id" : 0001},
{"participantsData.id": 1, "matchCreation": 1 })
This will give you the below result
{
"_id" : "myid",
"matchCreation" : 1463916465614,
"participantsData" : [
{
"id" : 1
}
]
}
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:
{ $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } }
To specify a <field> in an embedded document or in an array, use dot notation.
Try in the mongo shell
db.yourcollection.remove({books:[{title:'title_you_want'}]})
Careful with the braces.
I need get a specific object in array of array in MongoDB.
I need get only the task object = [_id = ObjectId("543429a2cb38b1d83c3ff2c2")].
My document (projects):
{
"_id" : ObjectId("543428c2cb38b1d83c3ff2bd"),
"name" : "new project",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b"),
"members" : [
ObjectId("5424ac37eb0ea85d4c921f8b")
],
"US" : [
{
"_id" : ObjectId("5434297fcb38b1d83c3ff2c0"),
"name" : "Test Story",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b"),
"tasks" : [
{
"_id" : ObjectId("54342987cb38b1d83c3ff2c1"),
"name" : "teste3",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b")
},
{
"_id" : ObjectId("543429a2cb38b1d83c3ff2c2"),
"name" : "jklasdfa_XXX",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b")
}
]
}
]
}
Result expected:
{
"_id" : ObjectId("543429a2cb38b1d83c3ff2c2"),
"name" : "jklasdfa_XXX",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b")
}
But i not getting it.
I still testing with no success:
db.projects.find({
"US.tasks._id" : ObjectId("543429a2cb38b1d83c3ff2c2")
}, { "US.tasks.$" : 1 })
I tryed with $elemMatch too, but return nothing.
db.projects.find({
"US" : {
"tasks" : {
$elemMatch : {
"_id" : ObjectId("543429a2cb38b1d83c3ff2c2")
}
}
}
})
Can i get ONLY my result expected using find()? If not, what and how use?
Thanks!
You will need an aggregation for that:
db.projects.aggregate([{$unwind:"$US"},
{$unwind:"$US.tasks"},
{$match:{"US.tasks._id":ObjectId("543429a2cb38b1d83c3ff2c2")}},
{$project:{_id:0,"task":"$US.tasks"}}])
should return
{ task : {
"_id" : ObjectId("543429a2cb38b1d83c3ff2c2"),
"name" : "jklasdfa_XXX",
"author" : ObjectId("5424ac37eb0ea85d4c921f8b")
}
Explanation:
$unwind creates a new (virtual) document for each array element
$match is the query part of your find
$project is similar as to project part in find i.e. it specifies the fields you want to get in the results
You might want to add a second $match before the $unwind if you know the document you are searching (look at performance metrics).
Edit: added a second $unwind since US is an array.
Don't know what you are doing (so realy can't tell and just sugesting) but you might want to examine if your schema (and mongodb) is ideal for your task because the document looks just like denormalized relational data probably a relational database would be better for you.
I have a document and I need to query mongodb database to return me all the documents which was inserted after current document.
Is it possible and how to do that query?
If you do not override the default _id field you can use that objectID (see the mongodb docs) to make a comparison by time. For instance, the following query will find all the documents that are inserted after curDoc has been inserted (assuming none overwrite the _id field):
>db.test.find({ _id : {$gt : curDoc._id}})
Note that these timestamps are not super granular, if you would like a finer grained view of the time that documents are inserted I encourage you to add your own timestamp field to the documents you are inserting and use that field to make such queries.
If you are using Insert time stamp as on of the parameter, you can query like below
> db.foo.find()
{ "_id" : ObjectId("514bf8bbbe11e483111af213"), "Name" : "abc", "Insert_time" : ISODate("2013-03-22T06:22:51.422Z") }
{ "_id" : ObjectId("514bf8c5be11e483111af214"), "Name" : "xyz", "Insert_time" : ISODate("2013-03-22T06:23:01.310Z") }
{ "_id" : ObjectId("514bf8cebe11e483111af215"), "Name" : "pqr", "Insert_time" : ISODate("2013-03-22T06:23:10.006Z") }
{ "_id" : ObjectId("514bf8eabe11e483111af216"), "Name" : "ijk", "Insert_time" : ISODate("2013-03-22T06:23:38.410Z") }
>
Here my Insert_time corresponds to the document inserted time, and following query will give you the documents after a particular Insert_time,
> db.foo.find({Insert_time:{$gt:ISODate("2013-03-22T06:22:51.422Z")}})
{ "_id" : ObjectId("514bf8c5be11e483111af214"), "Name" : "xyz", "Insert_time" : ISODate("2013-03-22T06:23:01.310Z") }
{ "_id" : ObjectId("514bf8cebe11e483111af215"), "Name" : "pqr", "Insert_time" : ISODate("2013-03-22T06:23:10.006Z") }
{ "_id" : ObjectId("514bf8eabe11e483111af216"), "Name" : "ijk", "Insert_time" : ISODate("2013-03-22T06:23:38.410Z") }
>