Question

Is there a simple way to do this?

Answer 1

At the moment there is no command in MongoDB that would do this. Please note the JIRA ticket with related feature request.

You could do something like:

db.<collection_name>.find().forEach(function(d){ db.getSiblingDB('<new_database>')['<collection_name>'].insert(d); });

Please note that with this, the two databases would need to share the same mongod for this to work.

Besides this, you can do a mongodump of a collection from one database and then mongorestore the collection to the other database.