To copy a database within a single mongod process, or between mongod servers, simply connect to the target mongod and use the :meth:`~pymongo.database.Database.command` method:

>>> from pymongo import MongoClient
>>> client = MongoClient('target.example.com')
>>> client.admin.command('copydb',
                         fromdb='source_db_name',
                         todb='target_db_name')

To copy from a different mongod server that is not password-protected:

>>> client.admin.command('copydb',
                         fromdb='source_db_name',
                         todb='target_db_name',
                         fromhost='source.example.com')

If the target server is password-protected, authenticate to the "admin" database:

>>> client = MongoClient('target.example.com',
...                      username='administrator',
...                      password='pwd')
>>> client.admin.command('copydb',
                         fromdb='source_db_name',
                         todb='target_db_name',
                         fromhost='source.example.com')

See the :doc:`authentication examples </examples/authentication>`.

If the source server is password-protected, use the copyDatabase function in the mongo shell.

Versions of PyMongo before 3.0 included a copy_database helper method, but it has been removed.