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如何处理数据库中字符串到域模型中bool的映射。考虑一个例子,将硬币翻转存储在数据库中。对于通常只有两个值的情况,如磁头或尾部。将db varchar映射到域对象bool
(注:我意识到这是在大多数情况下还可以存储在数据库中的bool更好,但认为这是一个学术活动)
我想真模型落得“正面”在数据库中,而“尾巴”在数据库中最终为False in the model。
from sqlalchemy.orm import mapper, sessionmaker
from sqlalchemy import Table, MetaData, Column, Integer, String, create_engine
from unittest import TestCase
class Foo(object):
def __init__(self, id, is_heads):
self.id = id
self.is_heads = is_heads
metadata = MetaData()
db_foo = Table(
'foo', metadata,
Column('id', Integer, primary_key=True),
Column('side', String(5), nullable=False)) # heads or tails
def data_map():
# what do I need to do here?
mapper(Foo, db_foo)
class TestMaps(TestCase):
def test_map(self):
# Setup
engine = create_engine('sqlite:///:memory:', echo=True)
metadata.create_all(engine, tables=[db_foo])
Session = sessionmaker(bind=engine)
session = Session()
data_map()
expected = Foo(1, False)
# Exercise
session.add(expected)
session.flush()
actual = session.query(Foo).first()
# Verify
self.assertEqual(expected, actual)