:mod:`rattail.mappers` Module
-----------------------------

.. automodule:: rattail.mappers

SQLAlchemy Mapper Extensions
============================

The following classes derive from ``sqlalchemy.orm.MapperExtension``, and may be added
to any mapper by passing an instance of the extension to ``mapper()``, e.g.::

   from sqlalchemy import *
   from sqlalchemy.orm import mapper
   from rattail import get_uuid
   from rattail.mappers import AutoIncrementer

   metadata = MetaData()

   my_things = Table(
       'my_things', metadata,
       Column('uuid', String(32), primary_key=True, default=get_uuid),
       Column('id', Integer),
       )

   class MyThing(object):
       pass

   mapper(
       MyThing, my_things,
       extension=AutoIncrementer(),
       )

.. autoclass:: rattail.mappers.AutoIncrementer