无法从sqlalchemy.ext.declarative导入*

Question

如果我尝试执行from sqlalchemy.ext.declarative import *，它会失败。我已经尝试过用pip uninstall sqlalchemy卸载包，然后再重新安装。我试过从Ubuntu存储库( python-sqlalchemy-package)中删除该版本，但没有安装。我找到了一个干净的目录，并尝试了相同的命令。还是不管用。这是sqlalchemy 0.7.8和0.7.9的两个版本。

这是回溯：

In [1]: from sqlalchemy.ext.declarative import *
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/home/nine/slask/<ipython-input-1-7f210e4ec48b> in <module>()
----> 1 from sqlalchemy.ext.declarative import *

/usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/__init__.py in <module>()
   1252 """
   1253
-> 1254 from .api import declarative_base, synonym_for, comparable_using, \
   1255     instrument_declarative, ConcreteBase, AbstractConcreteBase, \
   1256     DeclarativeMeta, DeferredReflection, has_inherited_table,\

/usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/api.py in <module>()
    101
    102
--> 103 class declared_attr(interfaces._MappedAttribute, property):
    104     """Mark a class-level method as representing the definition of
    105     a mapped property or special declarative member name.

AttributeError: 'module' object has no attribute '_MappedAttribute'

根据记录，我运行的是Ubuntu 12.04。

Answer 1

现在它起作用了。这是我所做的：

• 我使用pip卸载了sqla
• 手动删除了剩余的文件使用pip卸载了sqla，现在它可以工作了。