python3 sqlalchemy pymysql connect string

问题:

using python3, I can connect to mysql using pymysql. all works as expected. enclosed code works.

import pymysql  conn = pymysql.connect(host='127.0.0.1',  unix_socket='/home/jhgong/mysql/tmp/mysql.sock', user='root', passwd='my_pass', db='my_db', port='3333') cur = conn.cursor() cur.execute('select user from auth_users') for i in cur:     print(i) 

trying to get sqlalchemy to connect with pymysql, the default example strings don't seem to work. the above example does not work unless I declare both the port number and a unix_socket.

below is what I've been using to try and get sqlalchemy to connect. I assume that the socket and port number are both needed. I used connect_args to feed in a hash with the extra unix_socket location. no joy.

enclosed the the snippit I've been using that creates the error.

conarg = {    'unix_socket':'/home/jhgong/mysql/tmp/mysql.sock',    'db'         :'ice' } engine = create_engine('mysql+pymysql://root:my_pass@127.0.0.1:3333/my_db',   connect_args = conarg, echo=True) connection = engine.connect() 

with or without the db in conarg hash i get the following error:

>>> connection = engine.connect() 2013-01-17 13:04:20,819 INFO sqlalchemy.engine.base.Engine b'SELECT DATABASE()' 2013-01-17 13:04:20,819 INFO sqlalchemy.engine.base.Engine () Traceback (most recent call last):   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 724, in _do_get     return self._pool.get(wait, self._timeout)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/util/queue.py", line 163, in get     raise Empty sqlalchemy.util.queue.Empty  During handling of the above exception, another exception occurred:  Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 1574, in connect      return self._connection_cls(self, **kwargs)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 58, in __init__     self.__connection = connection or engine.raw_connection()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 1637, in raw_connection     return self.pool.unique_connection()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 182, in unique_connection     return _ConnectionFairy(self).checkout()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 398, in __init__     rec = self._connection_record = pool._do_get()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 744, in _do_get     con = self._create_connection()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 187, in _create_connection      return _ConnectionRecord(self)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/pool.py", line 284, in __init__     exec_once(self.connection, self)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/event.py", line 362, in exec_once     self(*args, **kw)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/event.py", line 379, in __call__     fn(*args, **kw)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/strategies.py", line 168, in first_connect     dialect.initialize(c)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/dialects/mysql/base.py", line 2005, in initialize     default.DefaultDialect.initialize(self, connection)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/default.py", line 183, in initialize     self._get_default_schema_name(connection)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/dialects/mysql/base.py", line 1970, in _get_default_schema_name     return connection.execute('SELECT DATABASE()').scalar()   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 645, in execute     params)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 791, in _execute_text     statement, parameters   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/base.py", line 854, in _execute_context     context)   File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/SQLAlchemy-0.8.0b1dev-py3.2.egg/sqlalchemy/engine/default.py", line 342, in do_execute     cursor.execute(statement, parameters)    File "/nfs/site/home/jhgongx/.local/lib/python3.2/site-packages/PyMySQL3-0.5-py3.2.egg/pymysql/cursors.py", line 105, in execute     query = query % escaped_args TypeError: unsupported operand type(s) for %: 'bytes' and 'tuple' 

it appears to be raising an error on empty pool queue. setting the size or type of pool queue has no effect.

any suggestions on how to figure this out?

回答1:

Try this very simple example:

import sqlalchemy from sqlalchemy.sql import select from sqlalchemy import Table, MetaData   def init():     try:         server = 'xx'         db = 'xx'         login = 'xx'         passwd = 'xx'         engine_str = 'mysql+mysqlconnector://{}:{}@{}/{}'.format(login, passwd, server, db)         engine = sqlalchemy.create_engine(engine_str, echo=False, encoding='utf-8')         connection = engine.connect()         metadata = MetaData()         t_servers = Table('your_table_here', metadata, autoload=True, autoload_with=engine)         s = select([t_servers])         result = connection.execute(s)         for row in result:             print(row['the_field'])     except Exception:         raise     finally:         connection.close() if __name__ == '__main__':     init() 

Mysql connector for Python 3 : download here

回答2:

I know this is late but the PyMySQL requirements mention CPython >= 2.6 or >= 3.3, it looks like you're using CPython 3.2 (the default version of python used), and that may be your problem.

文章来源: python3 sqlalchemy pymysql connect string