PynamoDB Save

A pythonic interface to Amazon's DynamoDB

Project README

======== PynamoDB

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A Pythonic interface for Amazon's DynamoDB <https://aws.amazon.com/dynamodb/>_.

DynamoDB is a great NoSQL service provided by Amazon, but the API is verbose. PynamoDB presents you with a simple, elegant API.

Useful links:

Installation

From PyPi::

$ pip install pynamodb

From GitHub::

$ pip install git+https://github.com/pynamodb/PynamoDB#egg=pynamodb

From conda-forge::

$ conda install -c conda-forge pynamodb

Basic Usage

Create a model that describes your DynamoDB table.

.. code-block:: python

from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute

class UserModel(Model):
    """
    A DynamoDB User
    """
    class Meta:
        table_name = "dynamodb-user"
    email = UnicodeAttribute(null=True)
    first_name = UnicodeAttribute(range_key=True)
    last_name = UnicodeAttribute(hash_key=True)

PynamoDB allows you to create the table if needed (it must exist before you can use it!):

.. code-block:: python

UserModel.create_table(read_capacity_units=1, write_capacity_units=1)

Create a new user:

.. code-block:: python

user = UserModel("John", "Denver")
user.email = "[email protected]"
user.save()

Now, search your table for all users with a last name of 'Denver' and whose first name begins with 'J':

.. code-block:: python

for user in UserModel.query("Denver", UserModel.first_name.startswith("J")):
    print(user.first_name)

Examples of ways to query your table with filter conditions:

.. code-block:: python

for user in UserModel.query("Denver", UserModel.email=="[email protected]"):
    print(user.first_name)

Retrieve an existing user:

.. code-block:: python

try:
    user = UserModel.get("John", "Denver")
    print(user)
except UserModel.DoesNotExist:
    print("User does not exist")

Upgrade Warning

The behavior of 'UnicodeSetAttribute' has changed in backwards-incompatible ways as of the 1.6.0 and 3.0.1 releases of PynamoDB.

See UnicodeSetAttribute upgrade docs <https://pynamodb.readthedocs.io/en/latest/release_notes.html>_ for detailed instructions on how to safely perform the upgrade.

Advanced Usage

Want to use indexes? No problem:

.. code-block:: python

from pynamodb.models import Model
from pynamodb.indexes import GlobalSecondaryIndex, AllProjection
from pynamodb.attributes import NumberAttribute, UnicodeAttribute

class ViewIndex(GlobalSecondaryIndex):
    class Meta:
        read_capacity_units = 2
        write_capacity_units = 1
        projection = AllProjection()
    view = NumberAttribute(default=0, hash_key=True)

class TestModel(Model):
    class Meta:
        table_name = "TestModel"
    forum = UnicodeAttribute(hash_key=True)
    thread = UnicodeAttribute(range_key=True)
    view = NumberAttribute(default=0)
    view_index = ViewIndex()

Now query the index for all items with 0 views:

.. code-block:: python

for item in TestModel.view_index.query(0):
    print("Item queried from index: {0}".format(item))

It's really that simple.

Want to use DynamoDB local? Just add a host name attribute and specify your local server.

.. code-block:: python

from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute

class UserModel(Model):
    """
    A DynamoDB User
    """
    class Meta:
        table_name = "dynamodb-user"
        host = "http://localhost:8000"
    email = UnicodeAttribute(null=True)
    first_name = UnicodeAttribute(range_key=True)
    last_name = UnicodeAttribute(hash_key=True)

Want to enable streams on a table? Just add a stream_view_type name attribute and specify the type of data you'd like to stream.

.. code-block:: python

from pynamodb.models import Model
from pynamodb.attributes import UnicodeAttribute
from pynamodb.constants import STREAM_NEW_AND_OLD_IMAGE

class AnimalModel(Model):
    """
    A DynamoDB Animal
    """
    class Meta:
        table_name = "dynamodb-user"
        host = "http://localhost:8000"
        stream_view_type = STREAM_NEW_AND_OLD_IMAGE
    type = UnicodeAttribute(null=True)
    name = UnicodeAttribute(range_key=True)
    id = UnicodeAttribute(hash_key=True)

Features

  • Python >= 3.7 support
  • An ORM-like interface with query and scan filters
  • Compatible with DynamoDB Local
  • Supports the entire DynamoDB API
  • Support for Unicode, Binary, JSON, Number, Set, and UTC Datetime attributes
  • Support for Global and Local Secondary Indexes
  • Provides iterators for working with queries, scans, that are automatically paginated
  • Automatic pagination for bulk operations
  • Complex queries
  • Batch operations with automatic pagination
  • Iterators for working with Query and Scan operations
Open Source Agenda is not affiliated with "PynamoDB" Project. README Source: pynamodb/PynamoDB
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