PynamoDB

PynamoDB is a layer of abstraction over the Python SDK wrapper for AWS DynamoDB. Following an ORM design, it allows for the definition of data models for DynamoDB and to perform all database transactions using a class-based interface. By doing this it also leverages the power and convenicen of OOP when incorporating DynamoDB as a database backend into a project. The design philosophy followed in this wrapper is to hide as much complexity and implementation details as possible from the end user of this library.

Example of model definition

The following lines of code define a data model for a DynamoDB table:

from pynamodb.models import Model, Key, Throughput

class Camera(Model):
        table_name = 'Camera'
        year = Key(name='year', key_type='hash', attr_type='N')
        title = Key(key_type='range', attr_type='N')
        provisioned_throughput = Throughput(read=10, write=10)

To create a table, it is enough to instantiate the class and start performing database transactions with it. PynamoDB will use the information available from within the class definition to obtain an object representation of the table corresponding with this class. If a table is not found, PynamoDB creates it automatically.

Database transactions

Insert an item into a table

camera = Camera(year=2005, title=2)
camera.create()

or

camera.create(year=2005, title=3)

-- TODO: batchwrite

Query interface

Get item

Camera.get(year=2005, title=2)

Query

Camera.query(year=2005)

-- TODO: implement support for conditional queries.

Scan

-- STILL TODO

Camera.scan()

Update an item

Delete an item

Update the table model

Command line interface

Alternatively, migrations can be performed manually from the command line with the following commands:

python3 manage.py makemigrations
python3 manage.py migrate

The first command will create a JSON migrations file and save it in a migrations_log directory. The second command will apply the migrations defiend in that file on the corresponding tables.