Combine update and query parts to form the upserted document in MongoDB?

You need to use $set operator along with upsert:true. Let us first create a collection with documents −

> db.updateWithUpsertDemo.insertOne({"StudentFirstName":"John","StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd2a61c345990cee87fd890") } > db.updateWithUpsertDemo.insertOne({"StudentFirstName":"Larry","StudentAge":23}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd2a624345990cee87fd891") } > db.updateWithUpsertDemo.insertOne({"StudentFirstName":"David","StudentAge":24}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd2a62c345990cee87fd892") }

Following is the query to display all documents from a collection with the help of find() method −

> db.updateWithUpsertDemo.find().pretty();

This will produce the following output −

{    "_id" : ObjectId("5cd2a61c345990cee87fd890"),    "StudentFirstName" : "John",    "StudentAge" : 21 } {    "_id" : ObjectId("5cd2a624345990cee87fd891"),    "StudentFirstName" : "Larry",    "StudentAge" : 23 } {    "_id" : ObjectId("5cd2a62c345990cee87fd892"),    "StudentFirstName" : "David",    "StudentAge" : 24 }

Following is the query to combine update and query parts to form the upserted document −

> db.updateWithUpsertDemo.update({_id: ObjectId("5cd2a624345990cee87fd891")},{"$set": {"StudentFirstName": "Chris"}}, {upsert:true}); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Let us check whether the field “StudentFirstName” has been changed or not −

> db.updateWithUpsertDemo.find().pretty();

This will produce the following output −

{    "_id" : ObjectId("5cd2a61c345990cee87fd890"),    "StudentFirstName" : "John",    "StudentAge" : 21 } {    "_id" : ObjectId("5cd2a624345990cee87fd891"),    "StudentFirstName" : "Chris",    "StudentAge" : 23 } {    "_id" : ObjectId("5cd2a62c345990cee87fd892"),    "StudentFirstName" : "David",    "StudentAge" : 24 }