54 lines
1.8 KiB
ReStructuredText
54 lines
1.8 KiB
ReStructuredText
.. _guide-connecting:
|
|
|
|
=====================
|
|
Connecting to MongoDB
|
|
=====================
|
|
|
|
To connect to a running instance of :program:`mongod`, use the
|
|
:func:`~mongoengine.connect` function. The first argument is the name of the
|
|
database to connect to. If the database does not exist, it will be created. If
|
|
the database requires authentication, :attr:`username` and :attr:`password`
|
|
arguments may be provided::
|
|
|
|
from mongoengine import connect
|
|
connect('project1', username='webapp', password='pwd123')
|
|
|
|
By default, MongoEngine assumes that the :program:`mongod` instance is running
|
|
on **localhost** on port **27017**. If MongoDB is running elsewhere, you may
|
|
provide :attr:`host` and :attr:`port` arguments to
|
|
:func:`~mongoengine.connect`::
|
|
|
|
connect('project1', host='192.168.1.35', port=12345)
|
|
|
|
|
|
Multiple Databases
|
|
==================
|
|
|
|
Multiple database support was added in MongoEngine 0.6. To use multiple
|
|
databases you can use :func:`~mongoengine.connect` and provide an `alias` name
|
|
for the connection - if no `alias` is provided then "default" is used.
|
|
|
|
In the background this uses :func:`~mongoengine.register_connection` to
|
|
store the data and you can register all aliases up front if required.
|
|
|
|
Individual documents can also support multiple databases by providing a
|
|
`db_alias` in their meta data. This allows :class:`~pymongo.dbref.DBRef` objects
|
|
to point across databases and collections. Below is an example schema, using
|
|
3 different databases to store data::
|
|
|
|
class User(Document):
|
|
name = StringField()
|
|
|
|
meta = {"db_alias": "user-db"}
|
|
|
|
class Book(Document):
|
|
name = StringField()
|
|
|
|
meta = {"db_alias": "book-db"}
|
|
|
|
class AuthorBooks(Document):
|
|
author = ReferenceField(User)
|
|
book = ReferenceField(Book)
|
|
|
|
meta = {"db_alias": "users-books-db"}
|