SQLModel: sqlalchemy.exc.ArgumentError: Column expression or FROM clause expected, - mysql

Question

I am using the SQLModel library to do a simple select() like described on their official website. However I am getting Column expression or FROM clause expected error message
from typing import Optional
from sqlmodel import Field, Session, SQLModel, create_engine, select
from models import Hero
sqrl = f"mysql+pymysql:///roo#asdf:localhost:3306/datab"
engine = create_engine(sqrl, echo=True)
def create_db_and_tables():
SQLModel.metadata.create_all(engine)
def select_heroes():
with Session(engine) as session:
statement = select(Hero)
results = session.exec(statement)
for hero in results:
print(hero)
def main():
select_heroes()
if __name__ == "__main__":
main()
this is my models/Hero.py code:
from datetime import datetime, date, time
from typing import Optional
from sqlmodel import Field, SQLModel
class Hero(SQLModel, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
name: str
secret_name: str
age: Optional[int] = None
created: datetime
lastseen: time
when I run app.py I get the sqlalchemy.exc.ArgumentError: Column expression or FROM clause expected, got <module 'models.Hero' from '/Users/dev/test/models/Hero.py'>. message

Answer 1

The error message <Column expression or FROM clause expected, got module 'models.Hero' from '/Users/dev/test/models/Hero.py'> tells us:
SQLModel / SQLAlchemy unexpectedly received a module object named models.Hero
that you have a module named Hero.py
The import statement from models import Hero only imports the module Hero. Either
change the import to import the model*
from models.Hero import Hero
change the code in select_heroes to reference the model†
statement = select(Hero.Hero)
* It's conventional to use all lowercase for module names; following this convention will help you distinguish between modules and models.
† This approach is preferable in my opinion: accessing the object via the module namespace eliminates the possibility of name collisions (of course it can be combined with lowercase module names).