You can use update command along with forEach() for large collection. Let us first create a collection with documents
>db.addingNewPropertyDemo.insertOne({"StudentName":"John","StudentAge":23,"CountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca1e61866324ffac2a7dc56") } >db.addingNewPropertyDemo.insertOne({"StudentName":"David","StudentAge":21,"CountryName":"AUS"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca1e62366324ffac2a7dc57") } >db.addingNewPropertyDemo.insertOne({"StudentName":"Bob","StudentAge":21,"CountryName":"UK"}); { "acknowledged" : true, "insertedId" : ObjectId("5ca1e62d66324ffac2a7dc58") }
Following is the query to display all documents from a collection with the help of find() method
> db.addingNewPropertyDemo.find().pretty();
This will produce the following output
{ "_id" : ObjectId("5ca1e61866324ffac2a7dc56"), "StudentName" : "John", "StudentAge" : 23, "CountryName" : "US" } { "_id" : ObjectId("5ca1e62366324ffac2a7dc57"), "StudentName" : "David", "StudentAge" : 21, "CountryName" : "AUS" } { "_id" : ObjectId("5ca1e62d66324ffac2a7dc58"), "StudentName" : "Bob", "StudentAge" : 21, "CountryName" : "UK" }
Following is the query to add new property to each document in a large collection
> db.addingNewPropertyDemo.find().forEach(function(data){ db.addingNewPropertyDemo.update({_id: data._id}, {$set: { StudentNameInUpperCase: data.StudentName.toUpperCase() }}) });
Let us check a new property is added or not
> db.addingNewPropertyDemo.find().pretty();
Following is the output displaying the new property as well
{ "_id" : ObjectId("5ca1e61866324ffac2a7dc56"), "StudentName" : "John", "StudentAge" : 23, "CountryName" : "US", "StudentNameInUpperCase" : "JOHN" } { "_id" : ObjectId("5ca1e62366324ffac2a7dc57"), "StudentName" : "David", "StudentAge" : 21, "CountryName" : "AUS", "StudentNameInUpperCase" : "DAVID" } { "_id" : ObjectId("5ca1e62d66324ffac2a7dc58"), "StudentName" : "Bob", "StudentAge" : 21, "CountryName" : "UK", "StudentNameInUpperCase" : "BOB" }
Look at the above sample output, StudentNameInUpperCase property is added.