How do I insert a record from one mongo database into another?

Question

As far as I see all commands operate on the same database in mongodb. I want to do something like this:

db.mySourceCollection.find().forEach( function(x){ db.theDestinationCollection.save(x)} );

where mySourceCollection is on liveDatabase and theDestinationCollection is on testDatabase.

Answer 1

use dbname doesn't work in scripted mode (i.e. when scripting the shell with javascript), so you should use the db.getSiblingDB() method instead to reassign the 'db' variable, e.g.:

db = db.getSiblingDB("otherdb")

More info here: http://www.mongodb.org/display/DOCS/Scripting+the+shell

Answer 2

Use use :-)

> var documents = db.mySourceCollection.find()
> use testDatabase
switched to db testDatabase
> documents.forEach(function(x){ db.theDestinationCollection.insert(x) })

db is used to refer to the currently connected database, however you can switch databases on the fly using the use command, as I've shown above.

Check out the help command in the shell -- it mentions this command and much more!