SQLAlchemyのセッションを学ぶ(セッション作成編)

#! /usr/local/bin/python
# -*- cording: utf-8 -*-

import sqlalchemy 
import sqlalchemy.orm
from datetime import datetime


class User(object):
    def __init__(self,account,password,e_mail):
        self.account = account
        self.password = password
        self.e_mail = e_mail
    def __repr__(self):
            return "User<'%s','%s'>" % (self.account, self.e_mail)

bind_name = 'sqlite:///:memory:'
engine = sqlalchemy.create_engine(bind_name, encoding="utf8")
metadata = sqlalchemy.MetaData(bind=engine)

t_users =  sqlalchemy.Table('users', metadata,
                            sqlalchemy.Column('id', sqlalchemy.Integer, primary_key=True, autoincrement=True),
                            sqlalchemy.Column('account', sqlalchemy.String(16), nullable=True),
                            sqlalchemy.Column('password', sqlalchemy.String(32), nullable=True),
                            sqlalchemy.Column('e_mail', sqlalchemy.String(128), nullable=True),
                            sqlalchemy.Column('f_name', sqlalchemy.String(64)),
                            sqlalchemy.Column('l_name', sqlalchemy.String(64)),
                            sqlalchemy.Column('post', sqlalchemy.String(64)),
                            sqlalchemy.Column('section', sqlalchemy.String(64)),
                            sqlalchemy.Column('create_date', sqlalchemy.DateTime, nullable=True, default=sqlalchemy.func.now()),
                            sqlalchemy.Column('last_modified', sqlalchemy.DateTime, nullable=True, default=sqlalchemy.func.now(), onupdate=sqlalchemy.func.current_timestamp()),
                            )

sqlalchemy.orm.mapper(User,t_users)

metadata.create_all()

>>> from settable import *
>>> Session = sqlalchemy.orm.sessionmaker(bind=engine)
>>> sess1 = Session()
>>> sess2 = Session()
>>> sess1 is sess2
False

>>> from settable import *
>>> Session = sqlalchemy.orm.scoped_session(sqlalchemy.orm.sessionmaker(bind=engine))
>>> sess1 = Session()
>>> sess2 = Session()
>>> sess1 is sess2
True