Collection Management

Document subclasses utilizing the Collection trait (which Queryable inherits) gain class-level active record behaviours. Additionally, Collection inherits Identified as well, providing an automatically generated ObjectId field named id which maps to the stored _id key. There is a fairly substantial number of collection metadata and calculated properties available.

Before much can be done, it will be necessary to get a reference to a MongoDB connection or database object. Begin by importing the client object from the pymongo package.

from pymongo import MongoClient

Then, open a connection to a MongoDB server, here, running locally. We can save some space by defining the database to utilize at the same time, and requesting a handle to the default database back without needing to refer to it by name a second time.

client = MongoClient('mongodb://localhost/test')
db = client.get_database()

Binding our Account class to a database will look up the collection name to use from the __collection__ attribute. Alternatively you could bind directly to a specific collection. Either way, binding will automatically apply the metadata options for data access and validation and enable the get_collection method to provide you the correct, configured object.

Account.bind(db)

Two class methods are provided for collection management requiring awareness of our metadata: create_collection and create_indexes. Creating the collection will create any declared indexes automatically by default. For other collection-level management operations it is recommended to utilize get_collection and issue calls to the PyMongo API directly.

Account.create_collection()

With the class bound you can now more easily interact with your documents in the collection.

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