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我注意到通过存储 datetime.datetime.maxSQLAlchemy==SQLAlchemy==0.8.1和从mysql-python==1.2.3to存储的行为发生了变化mysql-python==1.2.4。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它。

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

数据库（test_database）如下所示：

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 我就得到了这个结果。

(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，我最终在我的数据库中得到了一个可以为空的值。

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1 回答 1

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这是 MySQL 服务器 (5.6.X) 新版本中报告的错误，与小数秒的舍入有关。

有关更多信息，请参阅此链接： http ://bugs.mysql.com/bug.php?id=68760

解决这个问题的方法是四舍五入毫秒。

于 2013-07-08T20:27:06.230 回答