Databases Reference
In-Depth Information
APPENDIX B
mongo: The Shell
Throughout this text, we use the
mongo
binary, which is the database shell. We generally
assume that you are running it on the same machine as
mongod
and that you are running
mongod
on the default port, but if you are not, you can specify this on startup and have
the shell connect to another server:
$ bin/mongo staging.example.com:20000
This would connect to a
mongod
running at
staging.example.com
on port 20000.
The shell also, by default, starts out connected to the
test
database. If you'd like
db
to
refer to a different database, you can use
/
dbname
after the server address:
$ bin/mongo localhost:27017/admin
This connects to
mongod
running locally on the default port, but
db
will immediately
refer to the
admin
database.
You can also start the shell without connecting to any database by using the
--nodb
option. This is useful if you'd like to just play around with JavaScript or connect later:
$ bin/mongo --nodb
MongoDB shell version: 1.5.3
type "help" for help
>
Keep in mind that
db
isn't the only database connection you can have. You can connect
to as many databases as you would like from the shell, which can be handy in multi-
server environments. Simply use the
connect()
method, and assign the resulting con-
nection to any variable you'd like. For instance, with sharding, we might want
mongos
to refer to the
mongos
server and also have a connection to each shard:
> mongos = connect("localhost:27017")
connecting to: localhost:27017
localhost:27017
> shard0 = connect("localhost:30000")
connecting to: localhost:30000
localhost:30000
> shard1 = connect("localhost:30001")
