MongoDB – Drop Index:

In MongoDB, we can remove the index by using the command below. We need to provide the required fields on which the indexes need to be removed.

Syntax:

db.collection.dropIndex(fields)

First verify the indexes already created in a collection.

testset:PRIMARY>db.students.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "test.students"
        },
        {
                "v" : 1,
                "key" : {
                        "firstname" : 1
                },
                "name" : "firstname_1",
                "ns" : "test.students"
        },
        {
                "v" : 1,
                "key" : {
                        "firstname" : 1,
                        "city" : 1
                },
                "name" : "firstname_1_city_1",
                "ns" : "test.students"
        }
]

Drop the index on “firstname” field.

testset:PRIMARY>db.students.dropIndex({firstname:1})
{ "nIndexesWas" : 3, "ok" : 1 }

Now Verify the index that was removed

testset:PRIMARY>db.students.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "test.students"
        },
        {
                "v" : 1,
                "key" : {
                        "firstname" : 1,
                        "city" : 1
                },
                "name" : "firstname_1_city_1",
                "ns" : "test.students"
        }
]