MongoDB - update partial number of documents?

To update partial number of documents, set multi to true. Let us create a collection with documents −

> db.demo312.insertOne({"FirstName":"Robert"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e50ce16f8647eb59e56204a") } > db.demo312.insertOne({"FirstName":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e50ce19f8647eb59e56204b") } > db.demo312.insertOne({"FirstName":"Robert"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e50ce1cf8647eb59e56204c") } > db.demo312.insertOne({"FirstName":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e50ce20f8647eb59e56204d") } > db.demo312.insertOne({"FirstName":"Robert"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e50ce22f8647eb59e56204e") }

Display all documents from a collection with the help of find() method −

> db.demo312.find();

This will produce the following output −

{ "_id" : ObjectId("5e50ce16f8647eb59e56204a"), "FirstName" : "Robert" } { "_id" : ObjectId("5e50ce19f8647eb59e56204b"), "FirstName" : "Bob" } { "_id" : ObjectId("5e50ce1cf8647eb59e56204c"), "FirstName" : "Robert" } { "_id" : ObjectId("5e50ce20f8647eb59e56204d"), "FirstName" : "David" } { "_id" : ObjectId("5e50ce22f8647eb59e56204e"), "FirstName" : "Robert" }

Following is the query to update partial number of documents

> db.demo312.update({"FirstName":"Robert"},{$set:{"FirstName":"Sam"}},{multi:true}); WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })

Display all documents from a collection with the help of find() method −

> db.demo312.find();

This will produce the following output −

{ "_id" : ObjectId("5e50ce16f8647eb59e56204a"), "FirstName" : "Sam" } { "_id" : ObjectId("5e50ce19f8647eb59e56204b"), "FirstName" : "Bob" } { "_id" : ObjectId("5e50ce1cf8647eb59e56204c"), "FirstName" : "Sam" } { "_id" : ObjectId("5e50ce20f8647eb59e56204d"), "FirstName" : "David" } { "_id" : ObjectId("5e50ce22f8647eb59e56204e"), "FirstName" : "Sam" }