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Articles on Trending Technologies
Technical articles with clear explanations and examples
How do I display a list of objects based on a specific property with MongoDB?
To display a list of objects based on a specific property, use dot notation in find(). Let us create a collection with documents −> db.demo455.insertOne({"Information":{"Student":[{"Name":"Chris", "Age":22}]}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7e1876dbcb9adb296c95c5") } > db.demo455.insertOne({"Information":{"Student":[{"Name":"David", "Age":21}]}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7e1883dbcb9adb296c95c6") } > db.demo455.insertOne({"Information":{"Student":[{"Name":"Bob", "Age":24}]}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7e188adbcb9adb296c95c7") } > db.demo455.insertOne({"Information":{"Student":[{"Name":"Robert", "Age":21}]}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7e18bcdbcb9adb296c95c8") }Display all documents from a collection with the help of find() method −> db.demo455.find();This will produce the following output −{ "_id" : ObjectId("5e7e1876dbcb9adb296c95c5"), "Information" : { "Student" : [ { ...
Read MoreHow to continuously publish the latest N records with sorting using MongoDB?
To publish the latest N records with sorting, use sort() along with limit(). Here, set the number of records you want to show with limit(). Let us create a collection with documents −> db.demo454.insertOne({"ClientName":"Chris"});{ "acknowledged" : true, "insertedId" : ObjectId("5e7cce8cdbcb9adb296c95c0") } > db.demo454.insertOne({"ClientName":"John"});{ "acknowledged" : true, "insertedId" : ObjectId("5e7cce95dbcb9adb296c95c1") } > db.demo454.insertOne({"ClientName":"Bob"});{ "acknowledged" : true, "insertedId" : ObjectId("5e7cce9fdbcb9adb296c95c2") } > db.demo454.insertOne({"ClientName":"David"});{ "acknowledged" : true, "insertedId" : ObjectId("5e7ccea6dbcb9adb296c95c3") } > db.demo454.insertOne({"ClientName":"Mike"});{ "acknowledged" : true, "insertedId" : ObjectId("5e7cceafdbcb9adb296c95c4") }Display all documents from a collection with the help of find() method −> db.demo454.find();This ...
Read MoreHow to filter documents based on an array in MongoDB?
To filter documents based on an array, use $elemMatch. The $elemMatch operator matches documents that contain an array field.Let us create a collection with documents −> db.demo453.insertOne( ... { _id: 101, details: [ { Name: "David", Marks: 60 }, { Name: "Mike", Marks: 55} ] } ... ) { "acknowledged" : true, "insertedId" : 101 } > db.demo453.insertOne( ... { _id: 102, details: [ { Name: "Bob", Marks: 80 }, { Name: "Sam", Marks: 78} ] } ... ) { "acknowledged" : true, "insertedId" : 102 } > db.demo453.insertOne( ... { _id: 103, details: [ { Name: "Carol", Marks: 67 ...
Read MoreGet the aggregated result and find the count of repeated values in different MongoDB\\ndocuments
To get the count of repeated values in different documents, use aggregate(). Let us create a collection with documents −> db.demo452.insertOne({"StudentName":"John", "StudentAge":21});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b7e3371f552a0ebb0a6f3") } > db.demo452.insertOne({"StudentName":"John", "StudentAge":22});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b7e3671f552a0ebb0a6f4") } > db.demo452.insertOne({"StudentName":"John", "StudentAge":23});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b7e3971f552a0ebb0a6f5") } > db.demo452.insertOne({"StudentName":"David", "StudentAge":24});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b7e4371f552a0ebb0a6f6") } > db.demo452.insertOne({"StudentName":"David", "StudentAge":25});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b7e4571f552a0ebb0a6f7") }Display all documents from a collection with the help of find() method −> db.demo452.find();This will produce the following output −{ "_id" : ...
Read MoreHow to reach subdata in MongoDB and display a particular document?
In order to reach subdata, you need to use key in MongoDB. Let us create a collection with documents −>db.demo450.insertOne({"Information":{"StudentDetails":{"StudentName":"Chris", "StudentAge":21}}}); { "acknowledged" : true, "insertedId" : ObjectId("5e7b590e71f552a0ebb0a6e6") } >db.demo450.insertOne({"Information":{"StudentDetails":{"StudentName":"David", "StudentAge":23}}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b591a71f552a0ebb0a6e7") } >db.demo450.insertOne({"Information":{"StudentDetails":{"StudentName":"Mike", "StudentAge":22}}});{ "acknowledged" : true, "insertedId" : ObjectId("5e7b592271f552a0ebb0a6e8") }Display all documents from a collection with the help of find() method −> db.demo450.find();This will produce the following output −{ "_id" : ObjectId("5e7b590e71f552a0ebb0a6e6"), "Information" : { "StudentDetails" : { "StudentName" : "Chris", "StudentAge" : 21 } } } { "_id" : ObjectId("5e7b591a71f552a0ebb0a6e7"), "Information" : { "StudentDetails" : { ...
Read MoreWhat is the difference between deleteOne() and findOneAndDelete() operation in MongoDB?
The findOneAndDelete() deletes single documents from the collection on the basis of a filter and sort criteria as well as it returns the deleted document.The deleteOne() removes single document from the collection.Let us see an example and create a collection with documents −> db.demo448.insertOne({"Name":"Chris", "Age":21});{ "acknowledged" : true, "insertedId" : ObjectId("5e7a291cbbc41e36cc3caeca") } > db.demo448.insertOne({"Name":"David", "Age":23});{ "acknowledged" : true, "insertedId" : ObjectId("5e7a2926bbc41e36cc3caecb") } > db.demo448.insertOne({"Name":"Bob", "Age":22});{ "acknowledged" : true, "insertedId" : ObjectId("5e7a2930bbc41e36cc3caecc") }Display all documents from a collection with the help of find() method −> db.demo448.find();This will produce the following output −{ "_id" : ObjectId("5e7a291cbbc41e36cc3caeca"), ...
Read MoreHow to create a custom scrollbar with CSS?
To create a custom scrollbar with CSS, the code is as follows −Example Live Demo body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; height: 200vh; /*to create a scrollbar*/ } ::-webkit-scrollbar { width: 20px; } p { font-size: 40px; } ::-webkit-scrollbar-track { box-shadow: inset 0 0 5px grey; border-radius: 10px; } ::-webkit-scrollbar-thumb { background: rgb(75, 22, 161); border-radius: 2px; } ::-webkit-scrollbar-thumb:hover ...
Read MoreHow to create a browser window example with CSS?
To create a browser window example with CSS, the code is as follows −Example Live Demo body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; } * { box-sizing: border-box; } .menuBar { border: 3px solid #f1f1f1; border-top-left-radius: 4px; border-top-right-radius: 4px; } .menuRow { padding: 10px; background: #f1f1f1; border-top-left-radius: 4px; border-top-right-radius: 4px; } .browserField { float: left; ...
Read MoreHow to create a download link with HTML?
To create a download link with HTML, the code is as follows −Example Live Demo Download Link example Click on the image above to download it OutputThe above code will produce the following output −
Read MoreHow to detect whether the browser is online or offline with JavaScript?
To detect whether the browser is online or offline with JavaScript, the code is as follows −Example Live Demo Online or offline with JavaScript example Click the button below to check if you are online or not Check online/offline function checkOnlineOffline() { if(navigator.onLine===true){ document.querySelector('.sample').innerHTML = "You are connected to internet" } else { document.querySelector('.sample').innerHTML = "You are not connected to internet" } } OutputThe above code will produce the following output −On clicking the “Check online/offline” button −
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