Using the Mongo Shell

Abstract

The MongoDB data storage structures are similar to those of a SQL relational database. A MongoDB database is similar to an SQL database. A table in an SQL database is a collection in MongoDB. A row in an SQL database is a document in MongoDB. A column in an SQL database is a field in MongoDB. MongoDB distribution includes an interactive shell called the Mongo shell. The Mongo shell provides database commands of different kinds including aggregation commands (for example, the count command finds the number of documents in a collection), collection commands (for example, the create command creates a collection), and administration commands (for example, the copydb command copies a database instance). The Mongo shell provides various JavaScript Mongo shell helper methods for data operations and administration. Some of the database commands have the equivalent Mongo shell helper methods, while others don’t. In this chapter we shall discuss how to access the Mongo shell and run database commands and JavaScript helper methods on a database, collection, or document.