Update objects in a MongoDB documents array (nested updating)?

To update the objects in a document’s array, you need to use update() method. To understand the update() method, let us create a collection with document. The query to create a collection with document is as follows:

> db.updateObjects.insertOne({"CustomerId":1,"CustomerName":"Larry","TotalItems":100, ... "ItemDetails":[ ... { ... "NameOfItem":"Item_1", ... "Amount":450 ... }, ... { ... "NameOfItem":"Item_2", ... "Amount":500 ... }, ... { ... "NameOfItem":"Item_3", ... "Amount":200 ... } ... ] ... } ... );

The following is the output:

{    "acknowledged" : true,    "insertedId" : ObjectId("5c6d688b0c3d5054b766a769") }

Now you can display documents from a collection with the help of find() method. The query is as follows:

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

The following is the output displaying the documents from the collection created above:

{    "_id" : ObjectId("5c6d688b0c3d5054b766a769"),    "CustomerId" : 1,    "CustomerName" : "Larry",    "TotalItems" : 100,    "ItemDetails" : [       {          "NameOfItem" : "Item_1",          "Amount" : 450       },       {          "NameOfItem" : "Item_2",          "Amount" : 500       },       {          "NameOfItem" : "Item_3",          "Amount" : 200       }    ] }

Increment “Amount”:200 with value 130. The query is as follows. Here, we have used the $inc operator to increment the value of a field:

> db.updateObjects.update({"CustomerId":1,"ItemDetails.NameOfItem":"Item_3"}, {$inc:{"ItemDetails.$.Amount":130}}, ... false,true); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

We have successfully updated incremented the value. Let us display the document from the collection. The query is as follows:

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

The following is the output:

{    "_id" : ObjectId("5c6d688b0c3d5054b766a769"),    "CustomerId" : 1,    "CustomerName" : "Larry",    "TotalItems" : 100,    "ItemDetails" : [       {          "NameOfItem" : "Item_1",          "Amount" : 450       },       {          "NameOfItem" : "Item_2",          "Amount" : 500       },       {          "NameOfItem" : "Item_3",          "Amount" : 330       }    ] }

Look at the sample output, the Amount 200 is incremented with 130, which is 330 now.