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Limit number of values in a field using MongoDB?
To limit number of values in a field, use $slice operator.
Let us first create a collection with documents −
> db.numberOfValuesDemo.insertOne({"Values":[100,200,300,900,1000,98]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cefb736ef71edecf6a1f6ab")
}Display all documents from a collection with the help of find() method −
> db.numberOfValuesDemo.find().pretty();
Output
{
"_id" : ObjectId("5cefb736ef71edecf6a1f6ab"),
"Values" : [
100,
200,
300,
900,
1000,
98
]
}Following is the query to limit number of values in a field using MongoDB −
> db.numberOfValuesDemo.find({},{ "Values": { "$slice": 2 } } );Output
{ "_id" : ObjectId("5cefb736ef71edecf6a1f6ab"), "Values" : [ 100, 200 ] }
Updated on: 30-Jul-2019
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