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SQLAlchemy-style ORM for Amazon's DynamoDB

Project description

Flywheel

Build:build coverage
Documentation:http://flywheel.readthedocs.org/
Downloads:http://pypi.python.org/pypi/flywheel
Source:https://github.com/stevearc/flywheel

Object mapper for Amazon’s DynamoDB

Getting Started

This is what a basic model looks like (schema taken from this DynamoDB API documentation)

from flywheel import Model, Field, GlobalIndex

class GameScore(Model):
    __metadata__ = {
        'global_indexes': [
            GlobalIndex('GameTitleIndex', 'title', 'top_score')
        ],
    }
    userid = Field(hash_key=True)
    title = Field(range_key=True)
    top_score = Field(type=int)
    top_score_time = Field(type=datetime)
    wins = Field(type=int)
    losses = Field(type=int)

    def __init__(self, title, userid):
        self.title = title
        self.userid = userid

Create a new top score

>>> score = GameScore('Master Blaster', 'abc')
>>> score.top_score = 9001
>>> score.top_score_time = datetime.utcnow()
>>> engine.sync(score)

Get all top scores for a user

>>> scores = engine.query(GameScore).filter(userid='abc').all()

Get the top score for Galaxy Invaders

>>> top_score = engine.query(GameScore).filter(title='Galaxy Invaders')\
...     .first(desc=True)

Atomically increment a user’s “wins” count on Alien Adventure

>>> score = GameScore('Alien Adventure', 'abc')
>>> score.incr_(wins=1)
>>> engine.sync(score)

Get all scores on Comet Quest that are over 9000

>>> scores = engine.query(GameScore).filter(GameScore.top_score > 9000,
...                                         title='Comet Quest').all()

Changelog

0.5.3

  • Bug fix: Fix refresh when using custom-typed primary keys

0.5.2

  • Bug fix: Change limit behavior to match docs. query().limit() will limit the number of results, query().scan_limit() will limit number of items scanned

0.5.1

  • Feature: Add update_schema() method to Engine

0.5.0

  • Breakage: Removing support for overflow fields. The only fields flywheel will care about now are those that are explicitly set as a Field()
  • Flywheel no longer forces raise_on_conflict to be True when you sync changes to fields that are part of a composite field. It is now up to the user to avoid putting their composite fields into an inconsistent state.
  • Feature: sync() has a new argument, no_read, which changes the behavior for syncing models with no changes. Instead of performing a GET, it will leave them as-is. This should make it easer to perform batch syncs without worrying as much about wasted bandwidth on GETs.
  • Field has renamed the data_type argument to type (data_type will still work)

0.4.11

  • Bug fix: Boolean overflow fields no longer decoded as decimals

0.4.10

  • Feature: Add exists() method to Engine

0.4.9

  • Feature: Add save() method to Models
  • Feature: Add update_field() method to Engine

0.4.8

  • Bug fix: Bad function call in index_pk_dict_

0.4.7

  • New index_pk_dict_ method for constructing exclusive_start_key for index queries

0.4.6

  • Pass exclusive_start_key through to dynamo3

0.4.5

  • Bug fix: Calling refresh() could sometimes crash from unordered results.

0.4.4

  • Bug fix: Mutable field defaults are no longer shared among model instances

0.4.3

  • Bug fix: Incorrect ConditionalCheckFailedException when syncing changes to a Composite field.
  • Allow DateTimeType to be stored as a naive datetime.

0.4.2

  • Make the dict, list, and bool types backwards-compatible with the old json-serialized format
  • Allow queries to use in, not null, and a few other constraints that were missing
  • Models are smarter about marking fields as dirty for sync
  • Stopped using deprecated expected syntax for dynamo3

0.4.1

  • Warning: Stored datetime objects will now be timezone-aware
  • Warning: Stored datetime objects will now keep their microseconds

0.4.0

  • Breakage: Dropping support for python 3.2 due to lack of botocore support
  • Breakage: Changing the list, dict, and bool data types to use native DynamoDB types instead of JSON serializing
  • Breakage and bug fix: Fixing serialization of datetime and date objects (for more info see the commit)
  • Feature: Can now do ‘contains’ filters on lists
  • Feature: Fields support multiple validation checks
  • Feature: Fields have an easy way to enforce non-null values (nullable=False)

Data type changes are due to an update in the DynamoDB API

0.3.0

  • Breakage: Engine namespace is slightly different. If you pass in a string it will be used as the table name prefix with no additional ‘-‘ added.

0.2.1

  • Breakage: Certain queries may now require you to specify an index where it was auto-detected before
  • Feature: Queries can now filter on non-indexed fields
  • Feature: More powerful “sync-if” constraints
  • Feature: Can OR together filter constraints in queries

All changes are due to an update in the DynamoDB API

0.2.0

  • Breakage: Engine no longer accepts boto connections (using dynamo3 instead)
  • Breakage: Removing S3Type (no longer have boto as dependency)
  • Feature: Support Python 3.2 and 3.3
  • Feature: .count() terminator for queries
  • Feature: Can override throughputs in Engine.create_schema()
  • Bug fix: Engine namespace is truly isolated

0.1.3

  • Bug fix: Some queries fail when global index has no range key

0.1.2

  • Bug fix: Field names can begin with an underscore
  • Feature: Models have a nice default __init__ method

0.1.1

  • Bug fix: Can call incr_() on models that have not been saved yet
  • Bug fix: Model comparison with None

0.1.0

  • First public release

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