> db.orders.find({})
{ "_id" : ObjectId("5b78b933d62e262ddb055509"), "user_id" : "5b16d96a74be42566844e0b4", "game_id" : "5b11c56c6c71dc44976fba55", "seats" : { "_id" : ObjectId("5b78b933d62e262ddb05550a") }, "__v" : 0 }
{ "_id" : ObjectId("5bb135638625d21c0883fe1d"), "user_id" : "5b16d96a74be42566844e0b4", "game_id" : "5b11c56c6c71dc44976fba61", "seats" : { "_id" : ObjectId("5bb135638625d21c0883fe1e") }, "__v" : 0 }
The above is the output of find command on the orders stored in my Mongo Instance.
seats is an array of objects embedded in the orders schema. How can I view and fetch the array stored in Object seats?
seats is a cross-reference field which contains the ObjectIds to anther collection.
Are you using Mongoose? If so you need to use the populate method to fill in the objects on find etc.
Related
Hi I'm trying to remove multiple objects from an array that looks like this.
{
"_id" : ObjectId("5a7da1bda21d5f3e8cf005b3"),
"owner" : "1",
"group_name" : "PAASCU Board",
"group_members" : [
{
"faculty_name" : "Cheska Dela Rosa",
"faculty_number" : 2,
"_id" : ObjectId("5a7da1bda21d5f3e8cf005b5")
},
{
"faculty_name" : "Earl Sempio",
"faculty_number" : 7323,
"_id" : ObjectId("5a7da1bda21d5f3e8cf005b4")
},
{
"faculty_number" : 203,
"faculty_name" : "Sample",
"_id" : ObjectId("5a7dbf7952bd150a94d83958")
},
{
"faculty_number" : 8025,
"faculty_name" : "Sample Postman",
"_id" : ObjectId("5a7dc64a1cf5dd3d50167d53")
}
],
"__v" : 0 }
It works when I remove a single object using the $pull with this code.
db.getCollection('groups').update({_id: ObjectId("5a7da1bda21d5f3e8cf005b3")}, {$pull: {"group_members": {"faculty_number":8025}}})
But what if I want to remove multiple objects with different faculty_number? I tried using the $each method just like how I add multiple objects in the array but it doesn't work well.
Use $in operator to pass the list of faculty values to remove documents from embedded array. More here
Try
db.groups.update(
{"_id": ObjectId("5a7da1bda21d5f3e8cf005b3")},
{"$pull":{"group_members":{"faculty_number":{$in:[8025,7323]}}}}
)
I have a document in my mongo db collection :
{
"_id" : ObjectId("xxxxxxx"),
"ID" : "a_11",
"details_list" : [
{
"detail" : "detail_1",
"link" : "https://xxxxx/yyy"
},
{
"detail" : "detail_2",
"link" : "https://xxxxx/zzz"
}
],
"name" : "xyz"
}
I want to get the "name" of all other docs where details_list (which is list of dictionary itself) matches with any other document in the same collection.
I tried using $where clause as well. db.collection.find({"$where": details_list == details_list}) but it did not returned any value.
I have Database in which there are few collections.
In one collection the _id field is displaying as
"_id" : ObjectId("58b0196947c4f14490d18741")
While other collection is Displaying something like this
"_id" : {
"timestamp" : 1487170280,
"machineIdentifier" : 8083947,
"processIdentifier" : 12168,
"counter" : 5289607,
"time" : NumberLong("1487170280000"),
"date" : NumberLong("1487170280000"),
"timeSecond" : 1487070280
}
Not sure what is root cause for it.
I have the following DB:
{
"_id" : ObjectId("556da79a77f9f7465943ff93"),
"guid" : "a12345",
"update_day" : "12:05:10 02.06.15"
}
{
"_id" : ObjectId("556dc4509a0a6a002f97e972"),
"guid" : "bbbb",
"update_day" : "15:03:10 02.06.15"
"__v" : 0
}
{
"_id" : ObjectId("556dc470e57836242f5519eb"),
"guid" : "bbbb",
"update_day" : "15:03:10 02.06.15"
"__v" : 0
}
{
"_id" : ObjectId("556dc47c7e882d3c2fe9e0fd"),
"guid" : "bbbb",
"update_day" : "15:03:10 02.06.15"
"__v" : 0
}
I want to set the guid to be unique, so no to duplicate is possible (Like primary key in MYSQL). So the DB will look like this:
{
"_id" : ObjectId("556da79a77f9f7465943ff93"),
"guid" : "a12345",
"update_day" : "12:05:10 02.06.15"
}
{
"_id" : ObjectId("556dc4509a0a6a002f97e972"),
"guid" : "bbbb",
"update_day" : "15:03:10 02.06.15"
"__v" : 0
}
and when I will insert another "guid":"bbbb" (with the save command), it will fails.
While declaring schema in mongoose, do this
guid : { type : String, unique : true}
AND if you want mongodb to create the guid on its own (like _id) then do this
guid : { type : String, index : { unique : true} }
First, you have to deal with the current state of your MongoDB collection and delete all the duplicated documents.
One thing is sure : you won't be able to create the unique index with duplicates in your collection and dropDupes is now deprecated since the version 2.7.5 so you can't use it. By the way, it was removed because it was almost impossible to predict which document would be deleted in the process.
Two possible solutions :
Create a new collection. Create the unique index on this new collection and run a batch to copy all the documents from the old collection to the new one and make sure you ignore duplicated key error during the process.
Deal with it in your own collection manually :
make sure you won't insert more duplicated documents in your code,
run a batch on your collection to delete the duplicates (and make sure you keep the good one if they are not completely identical),
then add the unique index.
I would declare my guid like so in mongoose :
guid : { type : String, unique : true}
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") }
>