Use dot notation (e.g. advertisers.name) to query and retrieve fields from nested objects: db.agencies.find({ “advertisers.created_at”: { $gte: start, $lt: end } }, { _id: 1, program_ids: 1, “advertisers.name”: 1 } }).limit(1).toArray(); Reference: Retrieving a Subset of Fields and Dot Notation
Since pymongo version 3.7.0 and above count() is deprecated. Instead use Collection.count_documents. Running cursor.count or collection.count will result in following warning message: DeprecationWarning: count is deprecated. Use Collection.count_documents instead. To use count_documents the code can be adjusted as follows import pymongo db = pymongo.MongoClient() col = db[DATABASE][COLLECTION] find = {“test_set”:”abc”} sort = [(“abc”,pymongo.DESCENDING)] skip = …
In MongoDB 2.6, the Aggregation Framework has a new array $size operator you can use: > db.mycollection.insert({‘foo’:[1,2,3,4]}) > db.mycollection.insert({‘foo’:[5,6,7]}) > db.mycollection.aggregate([{$project: { count: { $size:”$foo” }}}]) { “_id” : ObjectId(“5314b5c360477752b449eedf”), “count” : 4 } { “_id” : ObjectId(“5314b5c860477752b449eee0”), “count” : 3 }
In Mongoose, you’d use Person.update per the documentation. In order to create a document if it doesn’t already exist, you need to pass { upsert : true } in the options hash as it defaults to false. i.e. Person.update( { name : ‘Ted’ }, { name : ‘Ted’, age : 50 }, { upsert : …
What framework are you using? This is not MongoDB shell and looks like some weird wrapper around MapReduce. In that case $unwind would not be available, and you need it for user in the aggregation framework. Here’s what you want in the mongo shell: db.articles.aggregate([ {$match: { class_date: { $gte: date } } }, {$project: …
Creating indexes in MongoDB is an idempotent operation. So running db.names.createIndex({name:1}) would create the index only if it didn’t already exist. The deprecated (as of MongoDB 3.0) alias for createIndex() is ensureIndex() which is a bit clearer on what createIndex() actually does. Edit: Thanks to ZitRo for clarifying in comments that calling createIndex() with the …
Yet again the MongoDB documentation comes to the rescue assuming that the collection actually is named “demo1.categories”: db.demo1.categories.find().forEach( function(x){db.demo2.categories.insert(x)} );
OK, this all comes down to permissions, but let’s take it step by step. When you run sudo mongod it does not load a config file at all, it literally starts with the compiled in defaults – port 27017, database path of /data/db etc. – that is why you got the error about not being …
You have two options to get your Object in the db: 1. Define it by yourself let YourSchema = new Schema({ inventoryDetails: { config: { count: { static: { value: { type: Number, default: 0 }, dataSource: { type: String } } } }, myType: { type: String } }, title: { static: { value: …
This is one of the primary use cases of Mongoose’s ‘remove’ middleware. clientSchema.pre(‘remove’, function(next) { // ‘this’ is the client being removed. Provide callbacks here if you want // to be notified of the calls’ result. Sweepstakes.remove({client_id: this._id}).exec(); Submission.remove({client_id: this._id}).exec(); next(); }); This way, when you call client.remove() this middleware is automatically invoked to clean …