我发现了一个很好的解决方案，它受sqlAlchemy文档中提到的Factory模式和声明性Mixins的启发。
对于复杂的多级继承方案，需要使用另一种方法@declared_attr.cascading。
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy import Column, Integer, String
from sqlalchemy import MetaData
from sqlalchemy.ext.declarative import declarative_base
from flask_sqlalchemy import sqlAlchemy
sqlALCHEMY_DATABASE_URI = 'sqlite:///' + '/tmp/test_app.db'
engine = create_engine(sqlALCHEMY_DATABASE_URI, echo=True)
# for vanilla
Base = declarative_base()
# for Flask (import from app once initialized)
db = sqlAlchemy()
class MachineMixin:
__tablename__ = 'machine'
id = Column(Integer, primary_key=True)
name = Column(String(100))
status = Column(Integer)
class ModelFactory:
@staticmethod
def create(which_model, which_parent):
if which_parent == 'flask_sqlalchemy':
parent = db.Model
elif which_parent == 'pure_sqlalchemy':
parent = Base
# Now use type() to interit, fill __dict__ and assign a name
obj = type(which_model.__name__ + '_' + which_parent,
(which_model, parent),
{})
return obj
test_scenario = 'pure_sqlalchemy' # 'flask_sqlalchemy'
Machine = ModelFactory.create(MachineMixin, test_scenario)
if test_scenario == 'flask_sqlalchemy':
db.Metadata.drop_all(bind=engine)
db.Metadata.create_all(bind=engine)
elif test_scenario == 'pure_sqlalchemy':
Base.Metadata.drop_all(bind=engine)
Base.Metadata.create_all(bind=engine)
Session = sessionmaker(bind=engine)
session = Session()
session.add(Machine(name='Bob', status=1))
session.commit()
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