MongoDB Documentation, Release 3.0.4 Data modification refers to operations that create, update, or delete data. In MongoDB, these operations modify the data of a single collection . For the update and delete operations, you can specify the criteria to select the documents to update or remove. In the following diagram, the insert operation adds a new document to the users collection. Data Modification 3.1.2 Related Features Indexes See Write Operations Overview (page 74) for more information. To enhance the performance of common queries and updates, MongoDB has full support for secondary indexes. These indexes allow applications to store a view of a portion of the collection in an efficient data structure. Most indexes store an ordered representation of all values of a field or a group of fields. Indexes may also enforce uniqueness (page 504), store objects in a geospatial representation (page 494), and facilitate text search (page 500). 59 3.1. MongoDB CRUD Introduction