To rebuild indexes, use reIndex(). Let us first create an index. Following is the query −
> db.demo42.createIndex({"StudentFirstName":1});
This will produce the following output −
{ "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 }
Following is the query to rebuild index in MongoDB −
> db.demo42.reIndex({"StudentFirstName":1});
This will produce the following output −
{ "nIndexesWas" : 2, "nIndexes" : 2, "indexes" : [ { "v" : 2, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "web.demo42" }, { "v" : 2, "key" : { "StudentFirstName" : 1 }, "name" : "StudentFirstName_1", "ns" : "web.demo42" } ], "ok" : 1 }