mongodb indexing

www.ig‮ditfi‬ea.com

In MongoDB, indexing is the process of creating indexes for collections to improve query performance. Indexes are data structures that store a small portion of the collection's data set in an easy-to-traverse form.

When you perform a query in MongoDB, the query optimizer analyzes the query and chooses the best index to use to perform the query. If there is no index that can be used to perform the query, MongoDB will perform a full collection scan, which can be slow for large collections.

To create an index in MongoDB, you can use the createIndex() method, which is available on the collection object. Here is an example of how to create an index on a collection named "mycollection":

db.mycollection.createIndex({field1: 1})

In this example, the createIndex({field1: 1}) method is used to create an index on the "field1" field in ascending order.

You can also create compound indexes in MongoDB by specifying multiple fields in the index definition. For example, to create a compound index on the "field1" and "field2" fields in ascending order, you can use the following index definition:

db.mycollection.createIndex({field1: 1, field2: 1})

In addition to creating indexes, you can also drop indexes using the dropIndex() method. For example, to drop the index on the "field1" field in the "mycollection" collection, you can use the following command:

db.mycollection.dropIndex({field1: 1})