output

(sqlalchemy) [11:53:29 PM] azathoth:~/src/misc
% python sqlthing.py
before adding to session: <Thing(id=None, content=None)>
after adding to session: <Thing(id=None, content=None)>
after commit: <Thing(id=1, content=pending)>
(sqlalchemy) [11:53:32 PM] azathoth:~/src/misc
%

sqlthing.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String
from sqlalchemy.orm import sessionmaker

Base = declarative_base()


class Thing(Base):
    __tablename__ = "things"

    id = Column(Integer, primary_key=True)
    content = Column(String, server_default="pending", default="pending")

    def __repr__(self):
        return "<Thing(id={}, content={})>".format(self.id, self.content)

engine = create_engine('sqlite:///:memory:', echo=False)
Session = sessionmaker(bind=engine)
Base.metadata.create_all(engine)

db_session = Session()
item = Thing()
print "before adding to session: " + str(item)
db_session.add(item)
print "after adding to session: " + str(item)
db_session.commit()
print "after commit: " + str(item)