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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 More
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 More
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 More
To insert an item to an already created array inside an object, use MongoDB $push. Let us create a collection with documents −> db.demo449.insertOne( ... { ... details1: { ... details2: [{ ... _id:new ObjectId(), ... Name:"Chris" ... }], ... details3: [{ ... _id:new ObjectId(), ... Name:"David" ... }] ... } ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e7a40e971f552a0ebb0a6e3") }Display all documents from ... Read More
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 More
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 More
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 More
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 −
To create a flip box with CSS, the code is as follows −Example Live Demo body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; margin:20px; } .flipCard { background-color: transparent; width: 300px; height: 300px; perspective: 1000px; } .innerCard { position: relative; width: 100%; height: 100%; text-align: center; transition: transform 0.6s; transform-style: preserve-3d; box-shadow: ... Read More
To find out if an element is hidden with JavaScript, the code is as follows −Example Live Demo body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .hiddenDiv { width: 100%; padding: 20px; text-align: center; background-color: lightblue; margin-top: 20px; display: none; font-size: 20px; } .showBtn { border: none; padding: 15px; font-size: 18px; background-color: rgb(86, 25, ... Read More