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To sort records in a collection, use sort() in MongoDB. Let us create a collection with documents −> db.demo32.insertOne({"Name":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e175158cfb11e5c34d898c5") } > db.demo32.insertOne({"Name":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5e17515ccfb11e5c34d898c6") } > db.demo32.insertOne({"Name":"Adam"}); { "acknowledged" : true, "insertedId" : Object0Id("5e175160cfb11e5c34d898c7") } > db.demo32.insertOne({"Name":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5e175165cfb11e5c34d898c8") } > db.demo32.insertOne({"Name":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5e17517bcfb11e5c34d898c9") }Display all documents from a collection with the help of find() method −> db.demo32.find();This will produce the following output −{ "_id" : ObjectId("5e175158cfb11e5c34d898c5"), "Name" ... Read More
To avoid using index, use hint() in MongoDB. Let us create a collection with documents −> db.demo31.createIndex({"StudentFirstName":1}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo31.insertOne({"StudentFirstName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174f8fcfb11e5c34d898c1") } > db.demo31.insertOne({"StudentFirstName":"Jace"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174f97cfb11e5c34d898c2") } > db.demo31.insertOne({"StudentFirstName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174f9ccfb11e5c34d898c3") } > db.demo31.insertOne({"StudentFirstName":"James"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174fa0cfb11e5c34d898c4") }Display all documents from a collection with the help of find() method −> db.demo31.find();This will produce the following ... Read More
To get array items in a MongoDB document, use the dot(.) notation. Let us create a collection with documents −> db.demo29.insertOne({"StudentDetails":[{"StudentName":"Chris", "StudentMarks":58}, {"StudentName":"Bob", "StudentMarks":69}]}); { "acknowledged" : true, "insertedId" : ObjectId("5e15fcc08f2315c2efc48e6e") } >db.demo29.insertOne({"StudentDetails":[{"StudentName":"David", "StudentMarks":97}, {"StudentName":"Carol", "StudentMarks":96}]}); { "acknowledged" : true, "insertedId" : ObjectId("5e15fcd38f2315c2efc48e6f") }Display all documents from a collection with the help of find() method −> db.demo29.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e15fcc08f2315c2efc48e6e"), "StudentDetails" : [ { "StudentName" : "Chris", "StudentMarks" : 58 }, ... Read More
For this, use find() and fetch a specific record. Let us create a collection with documents −> db.demo30.insertOne({"City":"New York"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174ceccfb11e5c34d898bd") } > db.demo30.insertOne({"City":"Los Angeles"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174d0ecfb11e5c34d898be") } > db.demo30.insertOne({"City":"Chicago"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174d18cfb11e5c34d898bf") } > db.demo30.insertOne({"City":"Los Angeles"}); { "acknowledged" : true, "insertedId" : ObjectId("5e174d1dcfb11e5c34d898c0") }Display all documents from a collection with the help of find() method −> db.demo30.find();This will produce the following output −{ "_id" : ObjectId("5e174ceccfb11e5c34d898bd"), "City" : "New York" } { "_id" : ObjectId("5e174d0ecfb11e5c34d898be"), "City" : ... Read More
Yes, we can use the “.” symbol in MongoDB collection name. Let us create a collection with documents −> db.getCollection('demo28.example'); web.demo28.example > > > db.getCollection('demo28.example').insertOne({"Name":"Chris", "Age":32}); { "acknowledged" : true, "insertedId" : ObjectId("5e15fbe48f2315c2efc48e6b") } > db.getCollection('demo28.example').insertOne({"Name":"Bob", "Age":31}); { "acknowledged" : true, "insertedId" : ObjectId("5e15fbec8f2315c2efc48e6c") } > db.getCollection('demo28.example').insertOne({"Name":"David", "Age":33}); { "acknowledged" : true, "insertedId" : ObjectId("5e15fbf38f2315c2efc48e6d") }Display all documents from a collection with the help of find() method −> db.getCollection('demo28.example').find().pretty();This will produce the following output −{ "_id" : ObjectId("5e15fbe48f2315c2efc48e6b"), "Name" : "Chris", "Age" : 32 } { "_id" : ObjectId("5e15fbec8f2315c2efc48e6c"), "Name" : ... Read More
For similar operation, you can use / searchLetter /. Let us first create a collection with documents −> db.demo26.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c9dc22d07d3b95082e79") } > db.demo26.insertOne({"StudentName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c9e022d07d3b95082e7a") } > db.demo26.insertOne({"StudentName":"Jones"}); { "acknowledged" : true, "insertedId" : ObjectId("5e14ca7222d07d3b95082e7b") } > db.demo26.insertOne({"StudentName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5e14ca7622d07d3b95082e7c") }Display all documents from a collection with the help of find() method −> db.demo26.find();This will produce the following output −{ "_id" : ObjectId("5e14c9dc22d07d3b95082e79"), "StudentName" : "Chris" } { "_id" : ObjectId("5e14c9e022d07d3b95082e7a"), "StudentName" : "John" } { ... Read More
To query from part of object in an array, use $findOne() and $all. Let us first create a collection with documents −> db.demo25.insertOne( ... { ... ... "Details":[ ... { ... "UserId":"Carol101", ... "UserName":"Carol" ... }, ... { ... "UserId":"David102", ... "UserName":"David" ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e14c86e22d07d3b95082e77") } > db.demo25.insertOne( ... { ... ... "Details":[ ... ... Read More
To push a computed expression in $group, use aggregate. Let us first create a collection with documents −> db.demo24.insertOne({"Id":100, "Status":true}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c58722d07d3b95082e72") } > db.demo24.insertOne({"Id":100, "Status":true}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c58a22d07d3b95082e73") } > db.demo24.insertOne({"Id":100, "Status":false}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c58f22d07d3b95082e74") } > db.demo24.insertOne({"Id":100, "Status":true}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c59122d07d3b95082e75") } > db.demo24.insertOne({"Id":100, "Status":false}); { "acknowledged" : true, "insertedId" : ObjectId("5e14c59222d07d3b95082e76") }Display all documents from a collection with the help of find() method −> db.demo24.find();This will produce the following output ... Read More
For sub array document in MongoDB, use aggregate along with $sort. Let us first create a collection with documents −> db.demo23.insertOne( ...{ ... ... "StudentDetails" : [{ ... "Name" : "David", ... "Age" : 23, ... ... }, { ... "Name" : "Adam", ... "Age" : 24, ... }] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e14c3eb22d07d3b95082e71") }Display all documents from a collection with the help of find() method −> db.demo23.find().pretty()This will produce the following ... Read More
Let us say our string is −string str = "3456";Now, to check whether the entered string is a number or not −str.All(c => char.IsDigit(c))The above returns true if the string is a number, else false.Here is the complete code −Example Live Demousing System; using System.Linq; namespace Demo { public class MyApplication { public static void Main(string[] args) { string str = "3456"; // checking if string is a number or not Console.WriteLine(str.All(c => char.IsDigit(c))); } } }OutputTrue