SQLAlchemy+pymysql错误: sqlalchemy.util.queue.Empty

Question

尝试在Ubuntu上运行Python3.2、SQLAlchemy0.8和MySQL5.2，但我仍然得到下面的错误。我正在使用pymysql (实际上是pymysql3)引擎。

模块监控

from sqlalchemy import create_engine, MetaData
from sqlalchemy.ext.declarative import declarative_base
Engine = create_engine('mysql+pymysql://user:mypass@localhost/mydb')
Base = declarative_base(Engine)
Metadata = MetaData(bind=Engine)

from sqlalchemy.orm import sessionmaker
from sqlalchemy import Table, Column, Integer
Session = sessionmaker(bind=Engine)
session = Session()

class Student(Base):
    __table__ = Table('student_name', Metadata,
    Column('id', Integer, primary_key=True),
    autoload=True)

这样，当我运行模块时，它会抛出如下所示的错误。我做错了什么？

Traceback (most recent call last):
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 757, in _do_get
return self._pool.get(wait, self._timeout)
 File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/util/queue.py", line 166, in get
raise Empty
sqlalchemy.util.queue.Empty

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/lukik/workspace/upark/src/monitor.py", line 12, in <module>
class Parking(Base):
File "/home/lukik/workspace/upark/src/monitor.py", line 15, in Parking
autoload=True)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/schema.py", line 333, in __new__
table._init(name, metadata, *args, **kw)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/schema.py", line 397, in _init
self._autoload(metadata, autoload_with, include_columns)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/schema.py", line 425, in _autoload
self, include_columns, exclude_columns
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/base.py", line 1604, in run_callable
with self.contextual_connect() as conn:
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/base.py", line 1671, in contextual_connect
self.pool.connect(),
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 272, in connect
return _ConnectionFairy(self).checkout()
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 425, in __init__
rec = self._connection_record = pool._do_get()
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 777, in _do_get
con = self._create_connection()
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 225, in _create_connection
return _ConnectionRecord(self)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/pool.py", line 322, in __init__
exec_once(self.connection, self)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/event.py", line 381, in exec_once
self(*args, **kw)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/event.py", line 398, in __call__
fn(*args, **kw)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/strategies.py", line 168, in first_connect
dialect.initialize(c)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/dialects/mysql/base.py", line 2052, in initialize
default.DefaultDialect.initialize(self, connection)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/default.py", line 172, in initialize
self._get_default_schema_name(connection)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/dialects/mysql/base.py", line 2019, in _get_default_schema_name
return connection.execute('SELECT DATABASE()').scalar()
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/base.py", line 664, in execute
params)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/base.py", line 808, in _execute_text
statement, parameters
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/base.py", line 871, in _execute_context
context)
File "/usr/local/lib/python3.2/dist-packages/SQLAlchemy-0.8.0b2-py3.2.egg/sqlalchemy/engine/default.py", line 322, in do_execute
cursor.execute(statement, parameters)
File "/usr/local/lib/python3.2/dist-packages/pymysql/cursors.py", line 105, in execute
query = query % escaped_args
TypeError: unsupported operand type(s) for %: 'bytes' and 'tuple'

Answer 1

mysql-connector-python和oursql在py3k下很适合我。

如何安装？

$ pip install mysql-connector-python

用法

Engine = create_engine('mysql+mysqlconnector://<USERNAME>:<PASSWD>@<HOSTNAME>:<PORT>/<DBNAME>')

Answer 2

暂时保持在py2k或其他DB驱动程序上。这是一个已知的SQLAlchemy错误：二六六三。