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How to improve the execution time of a query in MongoDB?
To improve the execution time of a query, use index along with unique:true. Let us create a collection with documents −
> db.demo193.createIndex({"LastName":1},{unique:true});
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.demo193.insertOne({"FirstName":"John","LastName":"Doe"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3ade1803d395bdc21346d1")
}
> db.demo193.insertOne({"FirstName":"John","LastName":"Smith"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3ade1f03d395bdc21346d2")
}
> db.demo193.insertOne({"FirstName":"David","LastName":"Miller"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3ade2803d395bdc21346d3")
}Display all documents from a collection with the help of find() method −
> db.demo193.find();
This will produce the following output −
{ "_id" : ObjectId("5e3ade1803d395bdc21346d1"), "FirstName" : "John", "LastName" : "Doe" }
{ "_id" : ObjectId("5e3ade1f03d395bdc21346d2"), "FirstName" : "John", "LastName" : "Smith" }
{ "_id" : ObjectId("5e3ade2803d395bdc21346d3"), "FirstName" : "David", "LastName" : "Miller" }Following is the query to find a value with quicker execution time −
> db.demo193.find({"LastName":"Smith"});This will produce the following output −
{ "_id" : ObjectId("5e3ade1f03d395bdc21346d2"), "FirstName" : "John", "LastName" : "Smith" }
Updated on: 27-Mar-2020
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