To create index in the background, use createIndex() method and set “background: true” as in the below syntax −db.yourCollectionName.createIndex({"yourFieldName1":1, "yourFieldName2":1}, {background: true} );Let us implement the above syntax in order to create index and set background −> db.indexCreationDemo.createIndex({"StudentName":1, "StudentAge":1}, {background: true} ); {    "createdCollectionAutomatically" : true,    "numIndexesBefore" : ... Read More

The collation introduced in version MongoDB 3.4. Maybe, you implemented collation in a previous version.For our example, we are using MongoDB version 4.0.5. Following is the query to check the current version on system −> db.version()This will produce the following output −4.0.5Let us first create a collection with documents −> ... Read More

To calculate average, use aggregate along with $avg. Let us first create a collection with documents −> db.calculateAverage.insertOne({'Value':[10, 20, 80]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e0383e3f5e889d7a51994dc") } > db.calculateAverage.insertOne({'Value':[12, 15, 16]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e0383edf5e889d7a51994dd") } > db.calculateAverage.insertOne({'Value':[30, 35, 40]}); {   ... Read More

To promote subfields to top level in projection, use $objectToArray and $arrayToObject. Let us first create a collection with documents:> db.promoteSubfieldsDemo.insertOne({'s':10, 'y':{'t':20, 'u':30, }}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e038004190a577c668b55d5") }Following is the query to display all documents from a collection with the help of find() method ... Read More

To delete specific record, use “$pull” and since we are updating the already created collection, use UPDATE().Let us create a collection with documents −> db.demo213.insertOne({ ...   "id": 101, ...   "details1": [ ...      { ...         "Name": "Chris", ...         "details2": ... Read More

To find a MongoDB document through a word, use find() and set the word like −word/iLet us create a collection with documents −> db.demo212.insertOne({"details":[{"Name":"John Doe"}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e2c7603d395bdc21346ff") } > db.demo212.insertOne({"details":[{"Name":"Chris Brown"}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e2c8003d395bdc2134700") } > db.demo212.insertOne({"details":[{"Name":"Robert ... Read More

To test the values, use $type. Let us create a collection with documents −> db.demo211.insertOne({id:101, "Name":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e298203d395bdc21346fa") } > db.demo211.insertOne({id:102, "Name":null}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3e2a5403d395bdc21346fb") }Display all documents from a collection with the help of find() method ... Read More

To get the count of a specific value in MongoDB, use aggregate(). Let us create a collection with documents −> db.demo210.insertOne( ...   { ...      details: [ ...         { ...            ClientName: "Robert" ...         }, ... ... Read More

To convert filed value to create datetime day of month, use MongoDB aggregate(). Let us create a collection with documents −> db.demo209.insertOne( ...   { ...      "_id" : "101", ...      "details" : [ ...         { ...            "dat" ... Read More

To convert numeric string to number, use parseInt() in MongoDB. Let us create a collection with documents −> db.demo208.insertOne( { "value":"50"} ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3d92d803d395bdc21346f6") } > db.demo208.insertOne( { "value":"2350"} ); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3d92dd03d395bdc21346f7") }Display all documents from ... Read More