db.collection.ensureIndex(keys, options)

mongo Shell Method

This page documents the mongo shell method, and does not refer to the MongoDB Node.js driver (or any other driver) method. For corresponding MongoDB driver API, refer to your specific MongoDB driver documentation instead.

Deprecated since version 3.0.0: db.collection.ensureIndex() has been replaced by db.collection.createIndex().

Creates an index on the specified field if the index does not already exist.

Additional Information