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Last active November 5, 2015 02:11
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SQLAlchemy Enum column type using python's enum34
# -*- coding: utf-8 -*-
from __future__ import absolute_import
from enum import Enum
from sqlalchemy.types import SchemaType, TypeDecorator
from sqlalchemy.types import Enum as SAEnum
class EnumType(SchemaType, TypeDecorator):
def __init__(self, enum, name):
self.enum = enum = name
members = (member.value for member in enum)
kwargs = {'name': name}
self.impl = SAEnum(*members, **kwargs)
def _set_table(self, table, column):
self.impl._set_table(table, column)
def copy(self):
return EnumType(self.enum,
def process_bind_param(self, enum_instance, dialect):
if enum_instance is None:
return None
return enum_instance.value
def process_result_value(self, value, dialect):
if value is None:
return None
return self.enum(value)
class DBEnum(Enum):
def __init__(self, db_repr, description=None):
if description is None:
description = db_repr
db_repr =
self._value_ = db_repr
self.description = description
def as_type(cls, name):
return EnumType(cls, name)
def get_description_mapping(cls):
return dict((, member.description) for member in cls)
class ClientType(DBEnum):
private = 'Private' # Database representation will be equal to enum name => 'private'
company = 'co', 'Company' # Database representation will be overriden, and will become => 'co'
class Client(declarative_base()):
type = sa.Column(ClientType.as_type('ck_client_type'), nullable=False)
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