w3resource
Mongodb Tutorial

MongoDB: db.collection.dropIndex() method

db.collection.dropIndex

The db.collection.dropIndex() method is used to removes a specified index on a collection.

Note: You cannot drop the default index on the _id field.

Syntax:

db.collection.dropIndex(index)

Parameter:

Name Description Required /
Optional
Type
index Specifies the index to drop. You can specify the index either by the index name or by the index specification document.
To drop a text index, specify the index name.
Required string or document

Example: MongoDB: db.collection.dropIndex() method

Here we have created a duplicate of restaurants collection restaurants1 and the following indexes we have created on restaurants1 collection.

> db.restaurants1.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "test.restaurants1"
        },
        {
                "v" : 1,
                "key" : {
                        "cuisine" : 1
                },
                "name" : "cuisine_1",
                "ns" : "test.restaurants1"
        },
        {
                "v" : 1,
                "key" : {
                        "cuisine" : 1,
                        "address.zipcode" : -1
                },
                "name" : "cuisine_1_address.zipcode_-1",
                "ns" : "test.restaurants1"
        }
]

The single field index on the fieldcuisinehas the user-specified name ofcuisine_1and the index specification document of{"cuisine":1}.

Now, the following statement will drop the index cuisine_1 index.


db.restaurants1.dropIndex( "cuisine_1" );

or 

db.restaurants1.dropIndex( { "cuisine": 1 } );

Here is the output

> db.restaurants1.dropIndex( "cuisine_1" );
{ "nIndexesWas" : 3, "ok" : 1 }

or 

> db.restaurants1.dropIndex( { "cuisine": 1 } );
{ "nIndexesWas" : 3, "ok" : 1 }

Now, lists the indexes again.


> db.restaurants1.getIndexes();
[
        {
                "v" : 1,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "test.restaurants1"
        },
        {
                "v" : 1,
                "key" : {
                        "cuisine" : 1,
                        "address.zipcode" : -1
                },
                "name" : "cuisine_1_address.zipcode_-1",
                "ns" : "test.restaurants1"
        }
]

Retrieve the restaurants data from here

Previous: db.collection.drop() method
Next: db.collection.dropIndexes() method



New Content: Composer: Dependency manager for PHP, R Programming