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MongoDB query to replace value in an array?
Use $set to replace value in an array. Let us first create a collection with documents −
> db.replaceValueInArrayDemo.insertOne({"StudentScores":[45,56,78]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd7f0421a844af18acdffb7")
}
> db.replaceValueInArrayDemo.insertOne({"StudentScores":[33,90,67]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd7f0521a844af18acdffb8")
}Following is the query to display all documents from a collection with the help of find() method −
> db.replaceValueInArrayDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cd7f0421a844af18acdffb7"),
"StudentScores" : [
45,
56,
78
]
}
{
"_id" : ObjectId("5cd7f0521a844af18acdffb8"),
"StudentScores" : [
33,
90,
67
]
}Following is the query to replace value in array −
> db.replaceValueInArrayDemo.update({_id: ObjectId("5cd7f0421a844af18acdffb7"), StudentScores:45}, {$set: {'StudentScores.$': 99}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Let us check the document once again −
> db.replaceValueInArrayDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cd7f0421a844af18acdffb7"),
"StudentScores" : [
99,
56,
78
]
}
{
"_id" : ObjectId("5cd7f0521a844af18acdffb8"),
"StudentScores" : [
33,
90,
67
]
}
Updated on: 30-Jul-2019
1K+ Views
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