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https://github.com/kvesteri/sqlalchemy-continuum

Versioning extension for SQLAlchemy.
https://github.com/kvesteri/sqlalchemy-continuum

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Versioning extension for SQLAlchemy.

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README 

        
SQLAlchemy-Continuum

====================



|Build Status| |Version Status| |Downloads|



Versioning and auditing extension for SQLAlchemy.



Features

--------



- Creates versions for inserts, deletes and updates

- Does not store updates which don't change anything

- Supports alembic migrations

- Can revert objects data as well as all object relations at given transaction even if the object was deleted

- Transactions can be queried afterwards using SQLAlchemy query syntax

- Query for changed records at given transaction

- Temporal relationship reflection. Version object's relationship show the parent objects relationships as they where in that point in time.

- Supports native versioning for PostgreSQL database (trigger based versioning)



QuickStart

----------



::



    pip install SQLAlchemy-Continuum



In order to make your models versioned you need two things:



1. Call make_versioned() before your models are defined.

2. Add __versioned__ to all models you wish to add versioning to



.. code-block:: python



    from sqlalchemy_continuum import make_versioned



    make_versioned(user_cls=None)



    class Article(Base):

        __versioned__ = {}

        __tablename__ = 'article'



        id = sa.Column(sa.Integer, primary_key=True, autoincrement=True)

        name = sa.Column(sa.Unicode(255))

        content = sa.Column(sa.UnicodeText)



    article = Article(name='Some article', content='Some content')

    session.add(article)

    session.commit()



    # article has now one version stored in database

    article.versions[0].name

    # 'Some article'



    article.name = 'Updated name'

    session.commit()



    article.versions[1].name

    # 'Updated name'



    # lets revert back to first version

    article.versions[0].revert()



    article.name

    # 'Some article'



For completeness, below is a working example.



.. code-block:: python



    from sqlalchemy_continuum import make_versioned

    from sqlalchemy import Column, Integer, Unicode, UnicodeText, create_engine

    from sqlalchemy.orm import create_session, configure_mappers, declarative_base



    make_versioned(user_cls=None)



    Base = declarative_base()

    class Article(Base):

        __versioned__ = {}

        __tablename__ = 'article'

        id = Column(Integer, primary_key=True, autoincrement=True)

        name = Column(Unicode(255))

        content = Column(UnicodeText)



    configure_mappers()

    engine = create_engine('sqlite://')

    Base.metadata.create_all(engine)

    session = create_session(bind=engine, autocommit=False)



    article = Article(name=u'Some article', content=u'Some content')

    session.add(article)

    session.commit()

    article.versions[0].name

    article.name = u'Updated name'

    session.commit()

    article.versions[1].name

    article.versions[0].revert()

    article.name



Resources

---------



- `Documentation `_

- `Issue Tracker `_

- `Code `_



.. image:: http://i.imgur.com/UFaRx.gif



.. |Build Status| image:: https://github.com/kvesteri/sqlalchemy-continuum/workflows/Test/badge.svg

   :target: https://github.com/kvesteri/sqlalchemy-continuum/actions?query=workflow%3ATest

.. |Version Status| image:: https://img.shields.io/pypi/v/SQLAlchemy-Continuum.png

   :target: https://pypi.python.org/pypi/SQLAlchemy-Continuum/

.. |Downloads| image:: https://img.shields.io/pypi/dm/SQLAlchemy-Continuum.png

   :target: https://pypi.python.org/pypi/SQLAlchemy-Continuum/



More information

----------------



- http://en.wikipedia.org/wiki/Slowly_changing_dimension

- http://en.wikipedia.org/wiki/Change_data_capture

- http://en.wikipedia.org/wiki/Anchor_Modeling

- http://en.wikipedia.org/wiki/Shadow_table

- https://wiki.postgresql.org/wiki/Audit_trigger

- https://wiki.postgresql.org/wiki/Audit_trigger_91plus

- http://kosalads.blogspot.fi/2014/06/implement-audit-functionality-in.html

- https://github.com/2ndQuadrant/pgaudit