python SqlModel官方文档示例不起作用

Question

我对我的pysimplegui项目的数据库和学习sqlmodel很陌生。我正在跟踪他们的官方文档，在这里我尝试了以下示例：示例

这是一个简单的初学者示例，但它似乎无法在我的机器上工作，我遵循了它们的文档(我的代码)中列出的所有基本步骤：

"""sql model"""
from sqlmodel import SQLModel, Field, create_engine, Session
from typing import Optional


class Hero(SQLModel, Table=True):
    """testing sqlmodel"""
    id: Optional = Field(default=None, primary_key=True)
    name: str
    secret_name: str
    age: Optional[int] = None


hero_1 = Hero(name="Deadpond", secret_name="Dive Wilson")
hero_2 = Hero(name="Spider-Boy", secret_name="Pedro Parqueador")
hero_3 = Hero(name="Rusty-Man", secret_name="Tommy Sharp", age=48)

engine = create_engine("sqlite:///database.db")

SQLModel.metadata.create_all(engine)
with Session(engine) as s:
    s.add(hero_1)
    s.add(hero_2)
    s.add(hero_3)
    s.commit()

当我运行脚本时，它给出了以下堆栈：

$ py model.py                                                          
Traceback (most recent call last):
  File "pydantic\validators.py", line 751, in pydantic.validators.find_validators            
TypeError: issubclass() arg 1 must be a class                                                
                                                                                             
During handling of the above exception, another exception occurred:                          
                                                                                             
Traceback (most recent call last):                                                           
  File "C:\Users\muham\Desktop\fun and learning\learning_mysql\model.py", line 6, in <module>
    class Hero(SQLModel):
  File "C:\Users\muham\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlmodel\main.py", line 272, in __new__
    new_cls = super().__new__(cls, name, bases, dict_used, **config_kwargs)
  File "pydantic\main.py", line 198, in pydantic.main.ModelMetaclass.__new__
  File "pydantic\fields.py", line 506, in pydantic.fields.ModelField.infer
  File "pydantic\fields.py", line 436, in pydantic.fields.ModelField.__init__
  File "pydantic\fields.py", line 557, in pydantic.fields.ModelField.prepare
  File "pydantic\fields.py", line 831, in pydantic.fields.ModelField.populate_validators
  File "pydantic\validators.py", line 760, in find_validators
RuntimeError: error checking inheritance of typing.Optional (type: Optional)

编辑：不知怎么的，我没有得到那个错误，但是现在我得到了这个错误：

$ py model.py 
Traceback (most recent call last):
  File "C:\Users\muham\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlalchemy\orm\session.py", line 2619, in add  
    state = attributes.instance_state(instance)                                                                                 
AttributeError: 'Hero' object has no attribute '_sa_instance_state'                                                             
                                                                                                                                
The above exception was the direct cause of the following exception:                                                            
                                                                                                                                
Traceback (most recent call last):                                                                                              
  File "C:\Users\muham\Desktop\fun and learning\learning_mysql\model.py", line 22, in <module>                                  
    s.add(hero_1)                                                                                                               
  File "C:\Users\muham\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlalchemy\orm\session.py", line 2621, in add  
    util.raise_(                                                                                                                
  File "C:\Users\muham\AppData\Local\Programs\Python\Python310\lib\site-packages\sqlalchemy\util\compat.py", line 208, in raise_
    raise exception                                                                                                             
sqlalchemy.orm.exc.UnmappedInstanceError: Class '__main__.Hero' is not mapped

Answer 1

似乎您从官方教程页面(参见：https://sqlmodel.tiangolo.com/)中错误复制了代码--您肯定遗漏了id值上的一个int。

这实际上是有效的(检查)：

from typing import Optional

from sqlmodel import Field, Session, SQLModel, create_engine


class Hero(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str
    secret_name: str
    age: Optional[int] = None


hero_1 = Hero(name="Deadpond", secret_name="Dive Wilson")
hero_2 = Hero(name="Spider-Boy", secret_name="Pedro Parqueador")
hero_3 = Hero(name="Rusty-Man", secret_name="Tommy Sharp", age=48)


engine = create_engine("sqlite:///database_2.db")


SQLModel.metadata.create_all(engine)

with Session(engine) as session:
    session.add(hero_1)
    session.add(hero_2)
    session.add(hero_3)
    session.commit()