http://stackoverflow.com/questions/35849727/sqlalchemy-automap-data-and-override-some-columns/38191497

gistfile1.txt

from sqlalchemy.ext.automap import automap_base
from sqlalchemy import create_engine, MetaData, Column, String, Integer
import pickle
from sqlalchemy.sql.schema import ForeignKey

# Create some tables in the database
engine = create_engine('sqlite://')
engine.execute('CREATE TABLE user (id INTEGER, name TEXT, favorite_color TEXT)')
engine.execute('CREATE TABLE profile (id INTEGER, userid INTEGER, summary TEXT)')

# Create a metadata based on the database
metadata = MetaData()
metadata.reflect(bind=engine)

# Pickle and unpickle the metadata
metadata = pickle.loads(pickle.dumps(metadata))

# Attempt to automap some classes and override some existing columns
Base = automap_base(metadata=metadata)

class User(Base):
    __tablename__ = 'user'

    id = Column('id', Integer, primary_key=True)
    name = Column('name', String)

class Profile(Base):
    __tablename__ = 'profile'
    id = Column('id', Integer, primary_key=True)
    userid = Column('userid', ForeignKey('user.id'))

Base.prepare()