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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.
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