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Found 6702 Articles for Database
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
2K+ Views
To update, use update() along with $set. Let us create a collection with documents −>db.demo134.insertOne({"EmployeeId":101, "EmployeeDetails":[{"EmployeeName":"Chris", "EmployeeAge":27}, {"EmployeeName":"Bob", "EmployeeAge":28}]}); { "acknowledged" : true, "insertedId" : ObjectId("5e319b2f68e7f832db1a7f7c") } >db.demo134.insertOne({"EmployeeId":102, "EmployeeDetails":[{"EmployeeName":"David", "EmployeeAge":24}, {"EmployeeName":"Carol", "EmployeeAge":29}]}); { "acknowledged" : true, "insertedId" : ObjectId("5e319b4468e7f832db1a7f7d") }Display all documents from a collection with the help of find() method −> db.demo134.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e319b2f68e7f832db1a7f7c"), "EmployeeId" : 101, "EmployeeDetails" : [ { "EmployeeName" : "Chris", "EmployeeAge" : 27 }, ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
2K+ Views
To group, use $week and $month in MongoDB. Let us create a collection with documents −> db.demo133.insertOne({"Rank":18, "DueDate":new ISODate("2020-01-10")}); { "acknowledged" : true, "insertedId" : ObjectId("5e31980968e7f832db1a7f78") } > db.demo133.insertOne({"Rank":12, "DueDate":new ISODate("2020-01-10")}); { "acknowledged" : true, "insertedId" : ObjectId("5e31982568e7f832db1a7f79") } > db.demo133.insertOne({"Rank":12, "DueDate":new ISODate("2020-02-01")}); { "acknowledged" : true, "insertedId" : ObjectId("5e31986568e7f832db1a7f7a") } > db.demo133.insertOne({"Rank":20, "DueDate":new ISODate("2020-02-01")}); { "acknowledged" : true, "insertedId" : ObjectId("5e31986c68e7f832db1a7f7b") }Display all documents from a collection with the help of find() method −> db.demo133.find();This will produce the following output −{ "_id" : ObjectId("5e31980968e7f832db1a7f78"), "Rank" : 18, "DueDate" : ISODate("2020-01-10T00:00:00Z") } ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
182 Views
To group across two columns, use $lookup. Let us create a collection with documents −> db.demo132.insertOne({"CountryName1":"US", "CountryName2":"UK", Value:50}); { "acknowledged" : true, "insertedId" : ObjectId("5e31950468e7f832db1a7f75") } > db.demo132.insertOne({"CountryName1":"UK", "CountryName2":"AUS", Value:10}); { "acknowledged" : true, "insertedId" : ObjectId("5e31951d68e7f832db1a7f76") } > db.demo132.insertOne({"CountryName1":"AUS", "CountryName2":"US", Value:40}); { "acknowledged" : true, "insertedId" : ObjectId("5e31952c68e7f832db1a7f77") }Display all documents from a collection with the help of find() method −> db.demo132.find();This will produce the following output −{ "_id" : ObjectId("5e31950468e7f832db1a7f75"), "CountryName1" : "US", "CountryName2" : "UK", "Value" : 50 } { "_id" : ObjectId("5e31951d68e7f832db1a7f76"), "CountryName1" : "UK", "CountryName2" : "AUS", "Value" : ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
883 Views
For this, use aggregate() in MongoDB. Let us first create a collection with documents −> db.demo131.insertOne( ... { ... "_id": 101, ... "Details": [ ... { ... "PlayerScore": 500, ... "PlayerName": "Chris" ... }, ... { ... "PlayerScore": 400, ... "PlayerName": "David" ... } ... ] ... } ... ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
153 Views
Let us first create a collection with documents −> db.demo130.insertOne( ... { ... ... "PlayerDetails":[{Score:56}, {Score:78}, {Score:89}, {Score:97}] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e3065bf68e7f832db1a7f6d") } > db.demo130.insertOne( ... { ... ... "PlayerDetails":[{Score:45}, {Score:56}] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e3065c068e7f832db1a7f6e") }Display all documents from a collection with the help of find() method −> db.demo130.find();This will produce the following output −{ "_id" : ObjectId("5e3065bf68e7f832db1a7f6d"), "PlayerDetails" : [ { "Score" : 56 }, { "Score" : 78 }, { "Score" : 89 }, ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
114 Views
To get distinct first words in a string, use split(). Let us first create a collection with documents −> db.demo129.insertOne({"Words":"This is the MySQL", "CountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5e305d6368e7f832db1a7f6b") } > db.demo129.insertOne({"Words":"MongoDB is NOSQL database", "CountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5e305d7b68e7f832db1a7f6c") }Display all documents from a collection with the help of find() method −> db.demo129.find();This will produce the following output −{ "_id" : ObjectId("5e305d6368e7f832db1a7f6b"), "Words" : "This is the MySQL", "CountryName" : "US" } { "_id" : ObjectId("5e305d7b68e7f832db1a7f6c"), "Words" : "MongoDB is NOSQL database", "CountryName" : "US" }Following is the query to ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
464 Views
To get distinct values from a column, use distinct() in MongoDB. Let us first create a collection with documents −> db.demo128.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e30583d68e7f832db1a7f5d") } > db.demo128.insertOne({"Name":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e30584068e7f832db1a7f5e") } > db.demo128.insertOne({"Name":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e30584368e7f832db1a7f5f") } > db.demo128.insertOne({"Name":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5e30584668e7f832db1a7f60") } > db.demo128.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e30584c68e7f832db1a7f61") }Display all documents from a collection with the help of find() method −> db.demo128.find();This will produce the following output −{ "_id" : ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
676 Views
For this, use aggregate() in MongoDB. Let us first create a collection with documents −> db.demo126.insertOne( ... { ... "StudentDetails" : { ... "Number" : 1, ... "OtherDetails" : [ ... { ... "Name" : "Chris", ... "Score" : 55 ... ... } ... ].. }} ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e304b3068e7f832db1a7f56") } > > > db.demo126.insertOne( ... { ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
598 Views
To remove a specific element, use $pull. Let us create a collection with documents −> db.demo125.insertOne({"ListOfNames":["John", "Chris", "Bob", "David", "Carol"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e2f304068e7f832db1a7f55") }Display all documents from a collection with the help of find() method −> db.demo125.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e2f304068e7f832db1a7f55"), "ListOfNames" : [ "John", "Chris", "Bob", "David", "Carol" ] }Following is the query to remove a specific element from array in MongoDB −> db.demo125.update( ... { }, ... { $pull: ... Read More
![AmitDiwan](https://www.tutorialspoint.com/assets/profiles/123055/profile/60_187394-1565938756.jpg)
502 Views
For this, use find() along with update(). Let us create a collection with documents −> db.demo124.insertOne( ... { ... "Name" : "John", ... "Id" : 101, ... "ProjectDetails" : [{ ... "ProjectName1" : "Online Book", ... "ProjectName2" : "Online Banking" ... }, { ... "ProjectName1" : "Online Library Management System", ... "ProjectName2" : "School Management System" ... }] ... } ... ); { "acknowledged" : true, "insertedId" ... Read More