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Create index in a MongoDB collection?
To create index, use createIndex() in MongoDB. Let us create a collection with documents −
> db.demo702.createIndex({"details.id":1}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo702.insertOne({ ... "details" : [ ... { ... id:101, ... studentInfo:{ ... "StudentName" : "Chris", ... "StudentAge" : 23, ... } ... }, ... { ... ... id: 102, ... studentInfo:{ ... "StudentName" : "Robert", ... "StudentAge" : 20, ... } ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5ea6ea3b551299a9f98c93b3") }
Display all documents from a collection with the help of find() method −
> db.demo702.find().pretty();
This will produce the following output −
{ "_id" : ObjectId("5ea6ea3b551299a9f98c93b3"), "details" : [ { "id" : 101, "studentInfo" : { "StudentName" : "Chris", "StudentAge" : 23 } }, { "id" : 102, "studentInfo" : { "StudentName" : "Robert", "StudentAge" : 20 } } ] }
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