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Found 1360 Articles for MongoDB
1K+ Views
Introduction to mongodb.connectThis method is used to connect the Mongo DB server with our Node application. This is an asynchronous method from MongoDB module.Syntaxmongodb.connect(path[, callback])Parameters•path – The server path where the MongoDB server is actually running along with its port.•callback – This function will give a callback if any error occurs.Installing Mongo-DBBefore proceeding to try connect your application with Nodejs, we need to setup our MongoDB server first.Use the following query to install mongoDB from npm.npm install mongodb –saveRun the following command to set up your mongoDB on the specific localhost server. This will help in creating connection with the ... Read More
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MongoDB is a widely used document database which is also a form of NoSQL DB. Python can interact with MongoDB through some python modules and create and manipulate data inside Mongo DB. In this article we will learn to do that. But MongoDB should already be available in your system before python can connect to it and run. To setup MongoDB in your system please visit our MongoDB tutorial here..Install pymongoTo interact with MongoDB we need the module names pymongo. Install it in your python environment using the below command.pip install pymogoCheck the Existing DBsWe now use this python module ... Read More
601 Views
To aggregate multiple result, use $group in MongoDB. Let us create a collection with documents −> db.demo765.insertOne( ... ... { ... Name:"John", ... "Category":"ComputerScience", ... "SubjectName":"MongoDB", ... "Marks":75 ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5eb054525637cd592b2a4b01") } > > db.demo765.insertOne( ... { ... Name:"John", ... "Category":"ComputerScience", ... "SubjectName":"MySQL", ... "Marks":85 ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5eb054525637cd592b2a4b02") } > db.demo765.insertOne( ... ... Read More
610 Views
Use $ne to check for not null. Let us create a collection with documents −> db.demo764.insertOne({"LoginUserName":"Chris", "LoginPassword":"Chris_12"}); { "acknowledged" : true, "insertedId" : ObjectId("5eb04ee55637cd592b2a4afc") } > db.demo764.insertOne({"LoginUserName":"Chris", "LoginPassword":null}); { "acknowledged" : true, "insertedId" : ObjectId("5eb04eee5637cd592b2a4afd") } > db.demo764.insertOne({"LoginUserName":"Chris", "LoginPassword":""}); { "acknowledged" : true, "insertedId" : ObjectId("5eb04ef35637cd592b2a4afe") }Display all documents from a collection with the help of find() method −> db.demo764.find();This will produce the following output −{ "_id" : ObjectId("5eb04ee55637cd592b2a4afc"), "LoginUserName" : "Chris", "LoginPassword" : "Chris_12" } { "_id" : ObjectId("5eb04eee5637cd592b2a4afd"), "LoginUserName" : "Chris", "LoginPassword" : null } { "_id" : ObjectId("5eb04ef35637cd592b2a4afe"), "LoginUserName" : "Chris", ... Read More
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To query on an array of objects for nested documents, use find(). Let us create a collection with documents −> db.demo763.insertOne( ... { ... _id:1, ... CountryName:"US", ... "studentInformation": [ ... { ... StudentName:"Chris", ... }, ... { ... StudentName:"David", ... StudentAge:22 ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : 1 }Display all documents from a collection with the help of find() method −> db.demo763.find();This will produce the following output −{ "_id" : 1, "CountryName" : "US", "studentInformation" : [ { "StudentName" : "Chris" }, { "StudentName" : "David", "StudentAge" : 22 } ] }Following is how to query an array of objects to fetch specific nested documents −> db.demo763.find({}, ... { ... studentInformation: { ... $elemMatch: { ... StudentAge: { ... $exists: true ... } ... } ... } ... })This will produce the following output −{ "_id" : 1, "studentInformation" : [ { "StudentName" : "David", "StudentAge" : 22 } ] }
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For this, use $project along with aggregate(). The $project in aggregation passes along the documents with the requested fields to the next stage in the pipeline.Let us create a collection with documents −> db.demo762.insertOne({ ... "_id" : { ... "userId":101, ... "userName":"Chris" ... }, .. . "countryName" : "US", ... ... "details" : [ ... { ... "Name" : "Robert", ... "DueDate" : "2020-04-10" ... ... }, ... ... { ... ... Read More
490 Views
To fetch a specific value from an array, use aggregate() along with $project. Let us create a collection with documents −> db.demo761.insertOne( ... { ... "details": [ ... { ... "student": { ... "FullName": "Chris Brown" ... } ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5eb034d15637cd592b2a4af1") } > db.demo761.insertOne( ... { ... ... Read More
429 Views
To update many documents with a single query, use bulkWrite() in MongoDB. Let us create a collection with documents −> db.demo760.insertOne({id:1, details:{Value1:100, Value2:50}}); { "acknowledged" : true, "insertedId" : ObjectId("5eb0309f5637cd592b2a4aee") } > db.demo760.insertOne({id:2, details:{Value1:60, Value2:70}}); { "acknowledged" : true, "insertedId" : ObjectId("5eb030a15637cd592b2a4aef") } > db.demo760.insertOne({id:3, details:{Value1:80, Value2:90}}); { "acknowledged" : true, "insertedId" : ObjectId("5eb030a15637cd592b2a4af0") }Display all documents from a collection with the help of find() method −> db.demo760.find();This will produce the following output −{ "_id" : ObjectId("5eb0309f5637cd592b2a4aee"), "id" : 1, "details" : { "Value1" : 100, "Value2" : 50 } } { "_id" : ... Read More
445 Views
For this, you need to use case insensitive (i). Let us create a collection with documents −> db.demo759.insertOne({SubjectName:"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5eb02ba95637cd592b2a4ae7") } > db.demo759.insertOne({SubjectName:"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5eb02baa5637cd592b2a4ae8") } > db.demo759.insertOne({SubjectName:"mongodb"}); { "acknowledged" : true, "insertedId" : ObjectId("5eb02baf5637cd592b2a4ae9") } > db.demo759.insertOne({SubjectName:"MONGODB"}); { "acknowledged" : true, "insertedId" : ObjectId("5eb02bb85637cd592b2a4aea") }Display all documents from a collection with the help of find() method −> db.demo759.find();This will produce the following output −{ "_id" : ObjectId("5eb02ba95637cd592b2a4ae7"), "SubjectName" : "MySQL" } { "_id" : ObjectId("5eb02baa5637cd592b2a4ae8"), "SubjectName" : "MongoDB" } { "_id" ... Read More
408 Views
For this, you can use $out along with aggregate() and $unwind. Let us create a collection with documents −> db.demo757.insertOne( ... { ... "id": 101, ... "Name": ["John", "Bob", "Chris"] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5eb025745637cd592b2a4ae2") } > db.demo757.insertOne( ... { ... "id": 102, ... "Name": ["David"] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5eb025755637cd592b2a4ae3") }Display all documents from a collection with the help of find() method −> db.demo757.find();This will produce the ... Read More