python - 每当我尝试在 main.py 文件中导入 models.py 时，它都会显示 sqlalchemy.exc.ArgumentError

Question

from xmlrpc.client import Boolean
from sqlalchemy import TIMESTAMP, Column, Integer, String
from sqlalchemy.sql.expression import text
from .database import Base

class Post(Base):
    __tablename__ = 'posts'

    id = Column(Integer, primary_key=True, nullable=False)
    title = Column(String, unique=True, nullable=False)
    content = Column(String, nullable=False)
    published = Column(Boolean, server_default='True', nullable=False)
    created_at= Column(TIMESTAMP(timezone=True), nullable= False, server_default=text)

我找不到错误。当我尝试使用models.Base.metadata.create_all(bind=engine)它创建表时，出现以下错误：

Traceback (most recent call last):
  File "C:\Users\MINTU\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlalchemy\sql\schema.py", line 125, in _init_items
    spwd = item._set_parent_with_dispatch
AttributeError: type object 'bool' has no attribute '_set_parent_with_dispatch'

The above exception was the direct cause of the following exception:

File "C:\Users\MINTU\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlalchemy\util\compat.py", line 207, in raise_
    raise exception
sqlalchemy.exc.ArgumentError: 'SchemaItem' object, such as a 'Column' or a 'Constraint' expected, got <class 'bool'>

Answer 1

首先，布尔值不能被导入from xmlrpc.client，但是from sqlalchemy

其次，你的表名不是写成tablename而是写成__tablename__。

第三，text必须TIMESTAMP用我会让你适应你的需要的论点来调用

from sqlalchemy import TIMESTAMP, Column, Integer, String, Boolean
from sqlalchemy.sql.expression import text
from .database import Base


class Post(Base): 
    __tablename__ = 'posts'

    id = Column(Integer, primary_key=True, nullable=False)
    title = Column(String, unique=True, nullable=False)
    content = Column(String, nullable=False)
    published = Column(Boolean, server_default='True', nullable=False)
    created_at= Column(TIMESTAMP(timezone=True), nullable= False, server_default=text('(now() at time zone "utc")'))