- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Found 1359 Articles for MongoDB
380 Views
To update, use update() and following is the syntax to create and use a sample custom variable −var anyVariableName=yourValue; db.yourCollectionName.update({filter}, {$set:{yourFieldName:yourVariableName}});Let us create a collection with documents −> db.demo600.insertOne({id:1, Name:"Robert"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a063f5f1e70e134e2699") } > db.demo600.insertOne({id:2, Name:"Mike"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a06bf5f1e70e134e269a") } > db.demo600.insertOne({id:3, Name:"Sam"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a072f5f1e70e134e269b") }Display all documents from a collection with the help of find() method −> db.demo600.find();This will produce the following output −{ "_id" : ObjectId("5e94a063f5f1e70e134e2699"), "id" : 1, "Name" : "Robert" } { "_id" : ObjectId("5e94a06bf5f1e70e134e269a"), "id" : 2, "Name" : "Mike" } ... Read More
288 Views
To subtract values from document field values, use $subtract in MongoDB aggregate(). Let us create a collection with documents −> db.demo599.insertOne({"TotalPrice":250, "DiscountPrice":35});{ "acknowledged" : true, "insertedId" : ObjectId("5e948192f5f1e70e134e2696") } > db.demo599.insertOne({"TotalPrice":400, "DiscountPrice":10});{ "acknowledged" : true, "insertedId" : ObjectId("5e948199f5f1e70e134e2697") } > db.demo599.insertOne({"TotalPrice":1550, "DiscountPrice":50});{ "acknowledged" : true, "insertedId" : ObjectId("5e9481a0f5f1e70e134e2698") }Display all documents from a collection with the help of find() method −> db.demo599.find();This will produce the following output −{ "_id" : ObjectId("5e948192f5f1e70e134e2696"), "TotalPrice" : 250, "DiscountPrice" : 35 } { "_id" : ObjectId("5e948199f5f1e70e134e2697"), "TotalPrice" : 400, "DiscountPrice" : 10 } { "_id" : ObjectId("5e9481a0f5f1e70e134e2698"), "TotalPrice" : 1550, "DiscountPrice" ... Read More
314 Views
For this, use $avg along with $group and aggregate(). Let us create a collection with documents −> db.demo598.insertOne( ... { ... Information:'Student', ... id:100, ... details:[ ... {Name:'Chris', Marks:75}, ... {Name:'Bob', Marks:55} ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e947fccf5f1e70e134e2694") } > db.demo598.insertOne( ... { ... Information:'Student', ... id:101, ... details:[ ... {Name:'Chris', Marks:75}, ... ... Read More
682 Views
To find which document contains a specific string, use $regex along with find(). Let us create a collection with documents −> db.demo597.insertOne({"Name":"John Doe"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947ae3f5f1e70e134e2690") } > db.demo597.insertOne({"Name":"John Smith"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947ae8f5f1e70e134e2691") } > db.demo597.insertOne({"Name":"Chris Brown"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947aeff5f1e70e134e2692") } > db.demo597.insertOne({"Name":"Adam Smith"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947afff5f1e70e134e2693") }Display all documents from a collection with the help of find() method −> db.demo597.find();This will produce the following output −{ "_id" : ObjectId("5e947ae3f5f1e70e134e2690"), "Name" : "John Doe" } { "_id" : ObjectId("5e947ae8f5f1e70e134e2691"), "Name" : "John Smith" } ... Read More
324 Views
Use findOne() in MongoDB for this. The findOne() returns one document that satisfies the specified query criteria on the collection.Let us create a collection with documents −> db.demo596.insertOne({_id:1, "FirstName":"John", "LastName":"Smith"}); { "acknowledged" : true, "insertedId" : 1 } > db.demo596.insertOne({_id:2, "FirstName":"John", "LastName":"Doe"}); { "acknowledged" : true, "insertedId" : 2 } > db.demo596.insertOne({_id:3, "FirstName":"Chris", "LastName":"Brown"}); { "acknowledged" : true, "insertedId" : 3 } > db.demo596.insertOne({_id:4, "FirstName":"David", "LastName":"Miller"}); { "acknowledged" : true, "insertedId" : 4 }Display all documents from a collection with the help of find() method −> db.demo596.find();This will produce the following output −{ "_id" : 1, "FirstName" : "John", "LastName" ... Read More
2K+ Views
Let us create a collection with documents −> db.demo595.insertOne( { "Information": [ { "_id": new ObjectId(), Name:"Chris" }, { _id:new ObjectId(), Name:"Robert" } ] } ); { "acknowledged" : true, "insertedId" : ObjectId("5e93369cfd2d90c177b5bce4") }Display all documents from a collection with the help of find() method −> db.demo595.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e93369cfd2d90c177b5bce4"), "Information" : [ { "_id" : ObjectId("5e93369cfd2d90c177b5bce2"), "Name" : "Chris" }, { "_id" : ObjectId("5e93369cfd2d90c177b5bce3"), ... Read More
103 Views
For this, use $slice. Let us create a collection with documents −> db.demo594.insertOne( ... { ... id:1, ... details:[ ... {Name:"Chris", Age:21}, ... {Name:"Bob", Age:20}, ... {Name:"David", Age:23}, ... {Name:"Sam", Age:22} ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e933459fd2d90c177b5bcdd") }Display all documents from a collection with the help of find() method −> db.demo594.find();This will produce the following output −{ "_id" : ObjectId("5e933459fd2d90c177b5bcdd"), "id" : 1, "details" ... Read More
359 Views
To fetch specific multiple documents in MongoDB, use $in. Let us create a collection with documents −> db.demo593.insertOne({id:1, "Name":"Chris"});{ "acknowledged" : true, "insertedId" : ObjectId("5e93177dfd2d90c177b5bcd9") } > db.demo593.insertOne({id:2, "Name":"John"});{ "acknowledged" : true, "insertedId" : ObjectId("5e931785fd2d90c177b5bcda") } > db.demo593.insertOne({id:3, "Name":"Bob"});{ "acknowledged" : true, "insertedId" : ObjectId("5e93178cfd2d90c177b5bcdb") } > db.demo593.insertOne({id:4, "Name":"Sam"});{ "acknowledged" : true, "insertedId" : ObjectId("5e931792fd2d90c177b5bcdc") }Display all documents from a collection with the help of find() method −> db.demo593.find();This will produce the following output −{ "_id" : ObjectId("5e93177dfd2d90c177b5bcd9"), "id" : 1, "Name" : "Chris" } { "_id" : ObjectId("5e931785fd2d90c177b5bcda"), "id" : 2, "Name" : "John" } ... Read More
164 Views
To match documents that contain an array field, use the $elemMatch operator. Let us create a collection with documents −> db.demo592.insertOne( ... { ... "id":101, ... "details" : [ ... { "Name" : "Chris", "Value" : "200"}, ... {"Name" : "David", "Value" : "800"} ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e930d8ffd2d90c177b5bcd6") } > db.demo592.insertOne( ... { ... id:102, ... "details" : [ ... { "Name" : "Chris", "Value" ... Read More
570 Views
To fetch a value from the nested document, use dot notation. Let us create a collection with documents −> db.demo591.insert([ ... { "Name": "John", "Age": 23 }, ... {"Name": "Carol", "Age": 26}, ... { "Name": "Robert", "Age": 29, ... details:[ ... { ... Email:"Robert@gmail.com", CountryName:"US"}, {"Post":35} ... ]} ... ]); BulkWriteResult({ "writeErrors" : [ ], "writeConcernErrors" : [ ], "nInserted" : 3, "nUpserted" : 0, "nMatched" : 0, "nModified" : 0, "nRemoved" : 0, "upserted" : [ ] ... Read More
To Continue Learning Please Login
Login with Google