Python 未插入Sqlalchemy查询参数
我使用SQLAlchemy声明性来处理MySQLPython 未插入Sqlalchemy查询参数,python,mysql,sqlalchemy,Python,Mysql,Sqlalchemy,我使用SQLAlchemy声明性来处理MySQL from sqlalchemy import * from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import relation, sessionmaker import datetime engine = create_engine('mysql+mysqldb://root:mypass@localhost/somedb') Base
from sqlalchemy import *
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relation, sessionmaker
import datetime
engine = create_engine('mysql+mysqldb://root:mypass@localhost/somedb')
Base = declarative_base()
Base.metadata.bind = engine
DBSession = sessionmaker(bind=engine)
session = DBSession()
class Item(Base):
__tablename__ = 'item'
id = Column(Integer, primary_key=True)
dt = Column(DateTime)
title = Column(UnicodeText)
Base.metadata.create_all(engine)
i = Item()
i.dt = datetime.datetime.now()
i.title = "hello world"
session.add(i)
session.commit()
此代码在session.commit上引发异常:
异常的完整堆栈跟踪在文章的末尾
我发现参数没有正确地插入到查询字符串中。文件MySQLdb/cursors.py的第163行有一行query=query.format*db.literalgs。查询变量是一个字符串。string.format函数接受替换字段,如{}、{1}、{23},而不是%s。但是查询变量中的替换字段是%s
因此,没有将参数插入到查询中
我可以通过修改sqlalchemy/sql/compiler.py文件变量BIND_模板来解决这个问题。我已将'format':%%s更改为'format':{}
但我清楚地知道,人们成功地使用了炼金术而没有这个错误。问题的真正原因是什么?也许我安装了一些不兼容的版本
我在Windows7x64上使用Python 3.4,
Mysql连接器:Mysql_python-1.2.3-py3.4-win-amd64.egg
异常的完整堆栈跟踪:
Traceback (most recent call last):
File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 3.1.3\helpers\pydev\pydevd.py", line 1539, in <module>
debugger.run(setup['file'], None, None)
File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 3.1.3\helpers\pydev\pydevd.py", line 1150, in run
pydev_imports.execfile(file, globals, locals) #execute the script
File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 3.1.3\helpers\pydev\_pydev_execfile.py", line 37, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc) #execute the script
File "C:/Work/midmay/midmay.parser/scripts/test.py", line 30, in <module>
session.commit()
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 765, in commit
self.transaction.commit()
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 370, in commit
self._prepare_impl()
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 350, in _prepare_impl
self.session.flush()
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 1903, in flush
self._flush(objects)
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 2021, in _flush
transaction.rollback(_capture_exception=True)
File "C:\Python34\lib\site-packages\sqlalchemy\util\langhelpers.py", line 57, in __exit__
compat.reraise(exc_type, exc_value, exc_tb)
File "C:\Python34\lib\site-packages\sqlalchemy\util\compat.py", line 168, in reraise
raise value
File "C:\Python34\lib\site-packages\sqlalchemy\orm\session.py", line 1985, in _flush
flush_context.execute()
File "C:\Python34\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 370, in execute
rec.execute(self)
File "C:\Python34\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 523, in execute
uow
File "C:\Python34\lib\site-packages\sqlalchemy\orm\persistence.py", line 64, in save_obj
mapper, table, insert)
File "C:\Python34\lib\site-packages\sqlalchemy\orm\persistence.py", line 594, in _emit_insert_statements
execute(statement, params)
File "C:\Python34\lib\site-packages\sqlalchemy\engine\base.py", line 720, in execute
return meth(self, multiparams, params)
File "C:\Python34\lib\site-packages\sqlalchemy\sql\elements.py", line 317, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "C:\Python34\lib\site-packages\sqlalchemy\engine\base.py", line 817, in _execute_clauseelement
compiled_sql, distilled_params
File "C:\Python34\lib\site-packages\sqlalchemy\engine\base.py", line 947, in _execute_context
context)
File "C:\Python34\lib\site-packages\sqlalchemy\engine\base.py", line 1108, in _handle_dbapi_exception
exc_info
File "C:\Python34\lib\site-packages\sqlalchemy\util\compat.py", line 174, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=exc_value)
File "C:\Python34\lib\site-packages\sqlalchemy\util\compat.py", line 167, in reraise
raise value.with_traceback(tb)
File "C:\Python34\lib\site-packages\sqlalchemy\engine\base.py", line 940, in _execute_context
context)
File "C:\Python34\lib\site-packages\sqlalchemy\engine\default.py", line 435, in do_execute
cursor.execute(statement, parameters)
File "C:\Python34\lib\site-packages\mysql_python-1.2.3-py3.4-win-amd64.egg\MySQLdb\cursors.py", line 184, in execute
self.errorhandler(self, exc, value)
File "C:\Python34\lib\site-packages\mysql_python-1.2.3-py3.4-win-amd64.egg\MySQLdb\connections.py", line 37, in defaulterrorhandler
raise errorvalue
File "C:\Python34\lib\site-packages\mysql_python-1.2.3-py3.4-win-amd64.egg\MySQLdb\cursors.py", line 171, in execute
r = self._query(query)
File "C:\Python34\lib\site-packages\mysql_python-1.2.3-py3.4-win-amd64.egg\MySQLdb\cursors.py", line 330, in _query
rowcount = self._do_query(q)
File "C:\Python34\lib\site-packages\mysql_python-1.2.3-py3.4-win-amd64.egg\MySQLdb\cursors.py", line 294, in _do_query
db.query(q)
sqlalchemy.exc.ProgrammingError: (ProgrammingError) (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '%s, %s)' at line 1") b'INSERT INTO item (dt, title) VALUES (%s, %s)' (datetime.datetime(2014, 5, 16, 20, 58, 7, 729245), 'hello world')
尝试添加uuu表u参数uuu={}。这对我很有用:
from sqlalchemy import *
from sqlalchemy.ext.declarative import declarative_base, DeferredReflection
from sqlalchemy.orm import relation, relationship
DeclarativeBase = declarative_base(cls=DeferredReflection)
class MyItem(DeclarativeBase):
__tablename__ = 'myitem'
__table_args__ = {}
更新:除了使用Python 2.7 x64在Linux上更改引擎的mysql url字符串外,我还运行了您的代码,它运行时没有任何问题—它创建了表并将“hello world”插入其中。依赖项:
MySQL-python==1.2.5
SQLAlchemy==0.9.2
仔细阅读您的帖子,我发现您使用了Python 3.4。国家:
所有SQLAlchemy模块和单元测试现在都可以用2.6版以后的任何Python解释器(包括3.1和3.2解释器)进行同样好的解释
这并没有明确提到3.3和3.4。您可能在SA中遇到了一个bug,或者只是3.4版还没有更新。我建议安装2.7,它们应该能够在单个系统上共存,使用virtualenv for 2.7,安装deps并重新运行代码
问题的另一个可能来源是3.4版本的MySQL驱动程序。很遗憾地说,Python3.*下对MySQL的支持严重不足:我工作场所的团队发现驱动程序不仅泄漏,而且在高负载下无法处理许多连接。在驱动程序修复之前,使用2.7可能会更好。或者干脆改成Postgres作为db。我找到了一个解决方案。也许它不是最好的,也不适合所有人。但是在这里。 解决方案是安装Mysql连接器而不是MySQLDb,并从Mysql更改连接字符串+mysqldb://root:mypass@localhost/somedb到mysql+connector://root:mypass@localhost/somedb 如果您和我一样是Windows用户,并且存在以下问题:,那么您可以将Python版本从3.4降级到3.3,并从这里下载用于Python 3.3的预编译Mysql连接器:
这对我有用。谢谢。\uuuuuu table\u args\uuuuu={}无法解决问题。添加列名并不太重要。
MySQL-python==1.2.5
SQLAlchemy==0.9.2