Mongo/Databases

Getting Info About Databases

Mongo shell

Start the mongo shell:

$ mongo
>

To list all available databases, use any of these commands:

> db.adminCommand('listDatabases')
> db.getMongo().getDBNames()
> show databases
> show dbs

Show all tables and collections in a database:

> use test_db
> show tables
> show collections
> db.getCollectionNames()

Command line

To bypass the javascript shell and run commands directly from the command line, run the commands using --eval:

mongo <dbname> --eval "db.getMongo().getDBNames()"
mongo <dbname> --eval "db.getCollectionNames()"
mongo <dbname> --eval "db.dropDatabase()"

Removing (Dropping) Databases

To remove (drop) a database, use the db.dropDatabase() function.

Dropping Databases from the Mongo Shell

From the mongo shell:

$ mongo
> use test_db
> db.dropDatabase()

Adding Databases

MongoDB has a simple approach to adding databases: just act like the database exists already, and if it does not, MongoDB will initialize it for you.

Adding Databases with Mongo Shell

After starting the mongo shell, I can create a test_db database by saying "use test_db":

$ mongo
> use test_db

You can always see the available databases using the show dbs command:

> show dbs
local     0.78125GB
test_db      0.23012GB

Note: a database with zero records in it will not show up when you run the show dbs command. Add records to see the database.

Resources

Administration commands: https://docs.mongodb.com/manual/reference/command/nav-administration/