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To combine or merge fields and then perform count, use $group along with $sum and $sort. Let us create a collection with documents −> db.demo647.insertOne({"Subject":"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c86316c954c74be91e6ee") } > db.demo647.insertOne({"Subject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c86356c954c74be91e6ef") } > db.demo647.insertOne({"Subject":"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c86376c954c74be91e6f0") } > db.demo647.insertOne({"Subject":"SQL Server"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c86406c954c74be91e6f1") } > db.demo647.insertOne({"Subject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c86436c954c74be91e6f2") } > db.demo647.insertOne({"Subject":"PL/SQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c864b6c954c74be91e6f3") } > db.demo647.insertOne({"Subject":"MongoDB"}); { ... Read More
Use forEach and check for the different elements and use save() along with some condition. Let us create a collection with documents −> db.demo646.insertOne( ... { ... ... "Information": [ ... { id: 100, Name:"Chris" }, ... { id: 100, Name:"Chris" }, ... { id: 101, Name:"David" }, ... { id: 100, Name:"Chris" } ... ], ... "different": [] ... } ... ) { "acknowledged" : true, "insertedId" : ObjectId("5e9c82ec6c954c74be91e6ed") }Display ... Read More
To store, let us see an example and create a collection with documents −> db.demo645.insertOne( ... { ... 'fileName' : 'MongoDB Program', ... 'fileLocation':'C:/users/workspace/AllMongoDBProgram/MongoDB Program' ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e9c78f36c954c74be91e6e8") } > > db.demo645.insertOne( ... { ... 'fileName' : 'SumOfTwoNumbers.java', ... 'fileLocation':'E:/eclipseWorkspace/AllJavaPrograms/SumOfTwoNumbers.java' ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e9c78f36c954c74be91e6e9") } > db.demo645.insertOne( ... { ... 'fileName' : 'Script.sql', ... 'fileLocation':'C:/MySQLQuery/Script.sql' ... } ... Read More
To update, use update() in MongoDB. To set it to current date, you need to get the current date −var todayDate = new Date();Let us first create a collection with documents −> db.demo644.insertOne({"ShippingDate":new ISODate("2018-04-19")}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c76896c954c74be91e6e6") } > db.demo644.insertOne({"ShippingDate":new ISODate("2019-01-10")}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c76966c954c74be91e6e7") }Display all documents from a collection with the help of find() method −> db.demo644.find();This will produce the following output −{ "_id" : ObjectId("5e9c76896c954c74be91e6e6"), "ShippingDate" : ISODate("2018-04-19T00:00:00Z") } { "_id" : ObjectId("5e9c76966c954c74be91e6e7"), "ShippingDate" : ISODate("2019-01-10T00:00:00Z") }Following is the query to update timestamp −> var todayDate ... Read More
To update bested documents in MongDB, use UPDATE() and positional($) operator. Let us create a collection with documents −> db.demo643.insertOne({ ... details : [ ... { ... "CountryName":"US", ... StudentDetails:[{Name:"Chris"}, {SubjectName:"MySQL"}] ... }, ... ... { ... "CountryName":"UK", ... StudentDetails:[{Name:"Bob"}, {SubjectName:"Java"}] ... } ... ] ... } ... ) { "acknowledged" : true, "insertedId" : ObjectId("5e9c737f6c954c74be91e6e3") }Display all documents from a collection with the help of find() method ... Read More
For this, use $all. The $all operator selects the documents where the value of a field is an array that contains all the specified elements. Let us create a collection with documents −> db.demo642.insertOne( ... { ... _id:1, ... ListOfNames:["Robert", "John"] ... } ... ); { "acknowledged" : true, "insertedId" : 1 } > db.demo642.insertOne( { _id:2, ListOfNames:["Robert", "Chris"] } ); { "acknowledged" : true, "insertedId" : 2 }Display all documents from a collection with the help of find() method −> db.demo642.find();This will produce the following output −{ "_id" : 1, "ListOfNames" ... Read More
To list collections, use getCollectionNames() in MongoDB. Following is the syntax −db.getCollectionNames();Let us implement the above syntax in order to list all collection names from the test database −> db.getCollectionNames();This will produce the following output −[ "arrayDemo", "arrayFieldIsNotEmptyDemo", "characterInFieldsDemo", "checkFieldExistDemo", "compareTwoFields", "comparingTwoFieldsDemo", "convertTextToDateTypeDemo", "countGroupByDemo", "demo407", "demo408", "demo409", "demo410", "demo411", "demo412", "demo413", "demo414", "demo415", "demo416", "demo417", "demo418", "demo419", "demo543", "demo544", "demo545", "demo546", "demo547", "demo548", "demo549", "demo550", "demo551", "demo552", "demo553", ... Read More
With HTML, you can create a simple drop-down list of items to get user input in HTML forms. A select box also called drop-down box provides an option to list down various options in the form of drop-down list, from where a user can select one or more options. The tag is used to create a drop-down list in HTML, with the tag.Here’s the list of attributes of tag:Sr.NoAttribute & Description1NameUsed to give a name to the control which is sent to the server to be recognized and get the value.2SizeThis can be used to present a ... Read More
To get specific elements, use $match with dot notation. Let us create a collection with documents −> db.demo641.insert( ... { ... ProductId:101, ... "ProductInformation": ... ( [ ... { ... ProductName:"Product-1", ... "ProductPrice":1000 ... }, ... { ... ProductName:"Product-2", ... "ProductPrice":500 ... ... Read More
If you want the first element from array, you can use $slice along with $gte. Let us create a collection with documents −> db.demo640.insertOne({Name:"John", "Scores":[80, 90, 75]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c2eb86c954c74be91e6e0") } > db.demo640.insertOne({Name:"Chris", "Scores":[85, 70, 89]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9c2ece6c954c74be91e6e1") }Display all documents from a collection with the help of find() method −> db.demo640.find();This will produce the following output −{ "_id" : ObjectId("5e9c2eb86c954c74be91e6e0"), "Name" : "John", "Scores" : [ 80, 90, 75 ] } { "_id" : ObjectId("5e9c2ece6c954c74be91e6e1"), "Name" : "Chris", "Scores" : [ 85, 70, 89 ] }Following ... Read More