MongoDB databases

Each MongoDB server instance can store several databases. Unless specifically defined, the MongoDB shell will automatically connect to the default test database. Let's switch to another database called mean by executing the following command:

> use mean

You'll see a command-line output telling you that the shell switched to the mean database. Notice that you didn't need to create the database before using it because in MongoDB, databases and collections are lazily created when you insert your first document. This behavior is consistent with MongoDB's dynamic approach to data. Another way to use a specific database is to run the shell executable with the database name as an argument, as follows:

$ mongo mean

The shell will then automatically connect to the mean database. If you want to list all the other databases in the current MongoDB server, just execute the following command:

> show dbs

This will show you a list of currently available databases that have at least...