【发布时间】：2013-06-23 07:37:40
【问题描述】：
我注意到通过SQLAlchemy==SQLAlchemy==0.8.1 存储datetime.datetime.max 并从mysql-python==1.2.3 到mysql-python==1.2.4 的行为发生了变化。通过仅将驱动程序从 1.2.3 更改为 1.2.4，我从能够存储变为无法存储。
在这件事上我该向哪里寻求帮助？ SQLAlchemy 还是 mysql-python？这是预期的行为还是错误，还是我的设置不正确？我担心这样的改变会破坏很多系统。
这是我的 SQLAlchemy 设置：
from sqlalchemy import create_engine, Integer, DateTime, Column
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from datetime import datetime
engine = create_engine('mysql://root@localhost/test_database', echo=True)
Base = declarative_base()
class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
age = Column(DateTime, default=datetime.max)
Base.metadata.create_all(engine)
session = sessionmaker(bind=engine)()
u = User()
session.add(u)
session.commit()
我还有一个名为 test 的 virtualenv。这就是我运行上面的代码时发生的情况。
(test)➜ ~ pip install MySQL-python==1.2.3
(test)➜ ~ python test.py
2013-06-26 10:29:18,885 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2013-06-26 10:29:18,885 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:29:18,887 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'character_set%%'
2013-06-26 10:29:18,887 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:29:18,891 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2013-06-26 10:29:18,891 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:29:18,896 INFO sqlalchemy.engine.base.Engine DESCRIBE `users`
2013-06-26 10:29:18,896 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:29:18,904 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2013-06-26 10:29:18,905 INFO sqlalchemy.engine.base.Engine INSERT INTO users (age) VALUES (%s)
2013-06-26 10:29:18,905 INFO sqlalchemy.engine.base.Engine (datetime.datetime(9999, 12, 31, 23, 59, 59, 999999),)
2013-06-26 10:29:18,908 INFO sqlalchemy.engine.base.Engine COMMIT
而数据库（test_database）看起来像这样：
mysql> select * from users;
+----+---------------------+
| id | age |
+----+---------------------+
| 1 | 9999-12-31 23:59:59 |
+----+---------------------+
1 row in set (0.00 sec)
这是我的预期结果，所以这里没什么奇怪的。
但是，只需将驱动程序切换到 mysql-python==1.2.4，我就会得到这个结果。
(test)➜ ~ pip install MySQL-python==1.2.4
(test)➜ ~ python test.py
2013-06-26 10:33:39,544 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2013-06-26 10:33:39,544 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:33:39,546 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'character_set%%'
2013-06-26 10:33:39,546 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:33:39,546 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2013-06-26 10:33:39,546 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:33:39,547 INFO sqlalchemy.engine.base.Engine DESCRIBE `users`
2013-06-26 10:33:39,547 INFO sqlalchemy.engine.base.Engine ()
2013-06-26 10:33:39,551 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2013-06-26 10:33:39,552 INFO sqlalchemy.engine.base.Engine INSERT INTO users (age) VALUES (%s)
2013-06-26 10:33:39,552 INFO sqlalchemy.engine.base.Engine (datetime.datetime(9999, 12, 31, 23, 59, 59, 999999),)
/Users/pelle/.virtualenvs/test/lib/python2.7/site-packages/sqlalchemy/engine/default.py:324: Warning: Datetime function: datetime field overflow
cursor.execute(statement, parameters)
/Users/pelle/.virtualenvs/test/lib/python2.7/site-packages/sqlalchemy/engine/default.py:324: Warning: Out of range value for column 'age' at row 1
cursor.execute(statement, parameters)
2013-06-26 10:33:39,553 INFO sqlalchemy.engine.base.Engine COMMIT
数据库看起来像这样。
mysql> select * from users;
+----+---------------------+
| id | age |
+----+---------------------+
| 1 | 0000-00-00 00:00:00 |
+----+---------------------+
1 row in set (0.00 sec)
所以现在突然间我收到了一个警告Warning: Datetime function: datetime field overflow，最后我的数据库中出现了一个可为空的值。
【问题讨论】：
标签： datetime python-2.7 sqlalchemy mysql-python