SQLAlchemy 错误：“TypeError：附加参数应命名为 <dialectname>_<argument>，得到 'nullable'”

Question

问题

在学习有关使用 Flash 的教程时，我在使用 Flask 时遇到错误。由于我是一个基本的 Python 程序员，我不明白它为什么或有什么问题。

所以如果你不介意解释它或添加一个解释链接。

控制台打印错误

（不知道什么是重要的，抱歉）

C:\Users\name\Desktop\Eeverything on this computer\GCSE\Computer Science\free-style\organised\website>python flaskblog.py
C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py:835: FSADeprecationWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True or False to suppress this warning.
  'SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and '
Traceback (most recent call last):
  File "flaskblog.py", line 22, in <module>
    class Post(db.Model):
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 67, in __init__
    super(NameMetaMixin, cls).__init__(name, bases, d)
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 121, in __init__
    super(BindMetaMixin, cls).__init__(name, bases, d)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\api.py", line 75, in __init__
    _as_declarative(cls, classname, cls.__dict__)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 131, in _as_declarative
    _MapperConfig.setup_mapping(cls, classname, dict_)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 160, in setup_mapping
    cfg_cls(cls_, classname, dict_)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 190, in __init__
    self._setup_table()
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 538, in _setup_table
    **table_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 99, in __table_cls__
    return sa.Table(*args, **kwargs)
  File "<string>", line 2, in __new__
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\deprecations.py", line 128, in warned
    return fn(*args, **kwargs)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 506, in __new__
    metadata._remove_table(name, schema)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
    raise value
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 501, in __new__
    table._init(name, metadata, *args, **kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 600, in _init
    self._init_items(*args)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 117, in _init_items
    spwd(self)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\base.py", line 457, in _set_parent_with_dispatch
    self.dispatch.after_parent_attach(self, parent)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\event\attr.py", line 322, in __call__
    fn(*args, **kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2094, in _set_table
    **self._unvalidated_dialect_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 3132, in __init__
    **dialect_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2711, in __init__
    self._validate_dialect_kwargs(dialect_kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\base.py", line 289, in _validate_dialect_kwargs
    "named <dialectname>_<argument>, got '%s'" % k
TypeError: Additional arguments should be named <dialectname>_<argument>, got 'nullable'

我的代码： flaskblog.py

C:\Users\name\Desktop\Eeverything on this computer\GCSE\Computer Science\free-style\organised\website>python flaskblog.py
C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py:835: FSADeprecationWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future.  Set it to True or False to suppress this warning.
  'SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and '
Traceback (most recent call last):
  File "flaskblog.py", line 22, in <module>
    class Post(db.Model):
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 67, in __init__
    super(NameMetaMixin, cls).__init__(name, bases, d)
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 121, in __init__
    super(BindMetaMixin, cls).__init__(name, bases, d)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\api.py", line 75, in __init__
    _as_declarative(cls, classname, cls.__dict__)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 131, in _as_declarative
    _MapperConfig.setup_mapping(cls, classname, dict_)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 160, in setup_mapping
    cfg_cls(cls_, classname, dict_)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 190, in __init__
    self._setup_table()
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\ext\declarative\base.py", line 538, in _setup_table
    **table_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\flask_sqlalchemy\model.py", line 99, in __table_cls__
    return sa.Table(*args, **kwargs)
  File "<string>", line 2, in __new__
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\deprecations.py", line 128, in warned
    return fn(*args, **kwargs)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 506, in __new__
    metadata._remove_table(name, schema)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
    raise value
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 501, in __new__
    table._init(name, metadata, *args, **kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 600, in _init
    self._init_items(*args)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 117, in _init_items
    spwd(self)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\base.py", line 457, in _set_parent_with_dispatch
    self.dispatch.after_parent_attach(self, parent)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\event\attr.py", line 322, in __call__
    fn(*args, **kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2094, in _set_table
    **self._unvalidated_dialect_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 3132, in __init__
    **dialect_kw
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2711, in __init__
    self._validate_dialect_kwargs(dialect_kw)
  File "C:\Users\name\Anaconda3\lib\site-packages\sqlalchemy\sql\base.py", line 289, in _validate_dialect_kwargs
    "named <dialectname>_<argument>, got '%s'" % k
TypeError: Additional arguments should be named <dialectname>_<argument>, got 'nullable'

相关文件

现在，我不知道您还需要什么，与此相关的其他文件称为：

    forms.py

    about.html
    home.html
    layout.html
    login.html
    register.html
    main.css

我没有添加它们，因为它最终可能会成为太多不必要的代码，但是如果您需要任何东西，请发表评论。

Answer 1

看起来你在user_id字段中打错字了Post类。

你写了：

    user_id = db.Column(db.Integer, db.ForeignKey("user.id", nullable=False))

正确的时候是：

    user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False)

Answer 2

就我而言，有一个拼写错误nullable=False

我写了 nunllable=False

修复拼写错误后解决 nullable=False