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Pushing values into array with multi field set to TRUE?
To push values, use $push along with update() with multi field set to TRUE. Let us create a collection with documents −
> db.demo747.insertOne({"CountryName":["US","IND"]}); { "acknowledged" : true, "insertedId" : ObjectId("5eae6a50a930c785c834e55f") } > db.demo747.insertOne({"CountryName":["UK","US"]}); { "acknowledged" : true, "insertedId" : ObjectId("5eae6a57a930c785c834e560") } > db.demo747.insertOne({"CountryName":["UK","IND"]}); { "acknowledged" : true, "insertedId" : ObjectId("5eae6a60a930c785c834e561") }
Display all documents from a collection with the help of find() method −
> db.demo747.find();
This will produce the following output −
{ "_id" : ObjectId("5eae6a50a930c785c834e55f"), "CountryName" : [ "US", "IND" ] } { "_id" : ObjectId("5eae6a57a930c785c834e560"), "CountryName" : [ "UK", "US" ] } { "_id" : ObjectId("5eae6a60a930c785c834e561"), "CountryName" : [ "UK", "IND" ] }
Following is the correct query to implement $push in update() −
> db.demo747.update({},{$push:{CountryName:"AUS"}},{multi:true}); WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })
Display all documents from a collection with the help of find() method −
> db.demo747.find();
This will produce the following output −
{ "_id" : ObjectId("5eae6a50a930c785c834e55f"), "CountryName" : [ "US", "IND", "AUS" ] } { "_id" : ObjectId("5eae6a57a930c785c834e560"), "CountryName" : [ "UK", "US", "AUS" ] } { "_id" : ObjectId("5eae6a60a930c785c834e561"), "CountryName" : [ "UK", "IND", "AUS" ] }
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