Indexing in MongoDB

Indexing in MongoDB

MongoDB uses indexes to make query processing more efficient. MongoDB would have to scan each document in the collection and retrieve only the documents that match the query without an index. An index is a special data structure that stores information about a document so that MongoDB can easily find the right data file. The index is sorted by the field's value specified by the index. Indexing: MongoDB provides a method called createIndex () that allows users to create indexes.

Indexes support the efficient resolution of queries. Without indexes, MongoDB must scan every collection document to select those documents that match the query statement. These scans are highly inefficient and require MongoDB to process a large volume of data.

Indexes are unique data structures that store a small portion of the data set in an easy-to-traverse form. The index stores the value of a specific field or set of fields, ordered by the field's value as specified in the index.

The createIndex() Method

To create an index, you need to use the createIndex() method of MongoDB.

The createIndex() method also has a number of optional parameters. These include:

  • background (Boolean)
  • unique (Boolean)
  • name (string)
  • sparse (Boolean)

Drop an Index

The dropIndex() methods can only delete one index at a time. To delete (or drop) multiple indexes from the collection, MongoDB provides the dropIndexes() method that takes multiple indexes as its parameters.

The dropIndex() methods can only delete one index at a time. To delete (or drop) multiple indexes from the collection, MongoDB provides the dropIndexes() method that takes multiple indexes as its parameters.

The dropIndexes() method

This method deletes multiple (specified) indexes on a collection.

The getIndexes() method in MongoDB describes all the indexes in the given collection.