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

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

For this, use $group in MongoDB aggregation. Let us create a collection with documents −> db.demo639.insertOne( ...    { ...       "_id" : 1, ...       "CountryName" : "US", ...       "Info1" : { ...          "Name" : "Chris", ...          "SubjectName" : "MySQL", ...          "Marks" : 78 ...       }, ...       "Info2" : { ...          "Name" : "Chris", ...          "SubjectName" : "MySQL", ...          "Marks" : 78 ... Read More

To filter items by fields and subfields, use dot notation. Let us create a collection with documents −> db.demo638.insert({Name:"Chris"}); WriteResult({ "nInserted" : 1 }) > db.demo638.insert({Name:"David", details:{Subject:"MongoDB"}}); WriteResult({ "nInserted" : 1 })Display all documents from a collection with the help of find() method −> db.demo638.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e9c28666c954c74be91e6de"), "Name" : "Chris" }    {       "_id" : ObjectId("5e9c28866c954c74be91e6df"),       "Name" : "David",       "details" : {          "Subject" : "MongoDB"    } }Following is the query to filter items by multiple fields and subfields −> ... Read More