User Guide Example throws AttributeError

[mkrd]

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Example Code

from typing import List, Optional

from sqlmodel import Field, Relationship, Session, SQLModel, create_engine


class Team(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    headquarters: str

    heroes: List["Hero"] = Relationship(back_populates="team")


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

    team_id: Optional[int] = Field(default=None, foreign_key="team.id")
    team: Optional[Team] = Relationship(back_populates="heroes")


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

engine = create_engine(sqlite_url, echo=True)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def create_heroes():
    with Session(engine) as session:
        team_preventers = Team(name="Preventers", headquarters="Sharp Tower")
        team_z_force = Team(name="Z-Force", headquarters="Sister Margaret’s Bar")

        hero_deadpond = Hero(
            name="Deadpond", secret_name="Dive Wilson", team=team_z_force
        )
        hero_rusty_man = Hero(
            name="Rusty-Man", secret_name="Tommy Sharp", age=48, team=team_preventers
        )
        hero_spider_boy = Hero(name="Spider-Boy", secret_name="Pedro Parqueador")
        session.add(hero_deadpond)
        session.add(hero_rusty_man)
        session.add(hero_spider_boy)
        session.commit()

        session.refresh(hero_deadpond)
        session.refresh(hero_rusty_man)
        session.refresh(hero_spider_boy)

        print("Created hero:", hero_deadpond)
        print("Created hero:", hero_rusty_man)
        print("Created hero:", hero_spider_boy)

        hero_spider_boy.team = team_preventers
        session.add(hero_spider_boy)
        session.commit()
        session.refresh(hero_spider_boy)
        print("Updated hero:", hero_spider_boy)

        hero_black_lion = Hero(name="Black Lion", secret_name="Trevor Challa", age=35)
        hero_sure_e = Hero(name="Princess Sure-E", secret_name="Sure-E")
        team_wakaland = Team(
            name="Wakaland",
            headquarters="Wakaland Capital City",
            heroes=[hero_black_lion, hero_sure_e],
        )
        session.add(team_wakaland)
        session.commit()
        session.refresh(team_wakaland)
        print("Team Wakaland:", team_wakaland)

        hero_tarantula = Hero(name="Tarantula", secret_name="Natalia Roman-on", age=32)
        hero_dr_weird = Hero(name="Dr. Weird", secret_name="Steve Weird", age=36)
        hero_cap = Hero(
            name="Captain North America", secret_name="Esteban Rogelios", age=93
        )

        team_preventers.heroes.append(hero_tarantula)
        team_preventers.heroes.append(hero_dr_weird)
        team_preventers.heroes.append(hero_cap)
        session.add(team_preventers)
        session.commit()
        session.refresh(hero_tarantula)
        session.refresh(hero_dr_weird)
        session.refresh(hero_cap)
        print("Preventers new hero:", hero_tarantula)
        print("Preventers new hero:", hero_dr_weird)
        print("Preventers new hero:", hero_cap)


def main():
    create_db_and_tables()
    create_heroes()


if __name__ == "__main__":
    main()

Description

Official Code Example from https://sqlmodel.tiangolo.com/tutorial/relationship-attributes/create-and-update-relationships/#include-relationship-objects-in-the-many-side

Running the code as instructed throws an AttributeError:

2022-05-19 10:57:57,546 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-05-19 10:57:57,546 INFO sqlalchemy.engine.Engine PRAGMA main.table_info("team")
2022-05-19 10:57:57,546 INFO sqlalchemy.engine.Engine [raw sql] ()
2022-05-19 10:57:57,547 INFO sqlalchemy.engine.Engine PRAGMA main.table_info("hero")
2022-05-19 10:57:57,547 INFO sqlalchemy.engine.Engine [raw sql] ()
2022-05-19 10:57:57,547 INFO sqlalchemy.engine.Engine COMMIT
2022-05-19 10:57:57,547 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-05-19 10:57:57,548 INFO sqlalchemy.engine.Engine INSERT INTO hero (name, secret_name, age, team_id) VALUES (?, ?, ?, ?)
2022-05-19 10:57:57,548 INFO sqlalchemy.engine.Engine [generated in 0.00006s] ('Deadpond', 'Dive Wilson', None, None)
2022-05-19 10:57:57,548 INFO sqlalchemy.engine.Engine INSERT INTO hero (name, secret_name, age, team_id) VALUES (?, ?, ?, ?)
2022-05-19 10:57:57,548 INFO sqlalchemy.engine.Engine [cached since 0.0004535s ago] ('Rusty-Man', 'Tommy Sharp', 48, None)
2022-05-19 10:57:57,549 INFO sqlalchemy.engine.Engine INSERT INTO hero (name, secret_name, age, team_id) VALUES (?, ?, ?, ?)
2022-05-19 10:57:57,549 INFO sqlalchemy.engine.Engine [cached since 0.0005178s ago] ('Spider-Boy', 'Pedro Parqueador', None, None)
2022-05-19 10:57:57,549 INFO sqlalchemy.engine.Engine COMMIT
2022-05-19 10:57:57,550 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine SELECT hero.id, hero.name, hero.secret_name, hero.age, hero.team_id 
FROM hero 
WHERE hero.id = ?
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine [generated in 0.00007s] (7,)
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine SELECT hero.id, hero.name, hero.secret_name, hero.age, hero.team_id 
FROM hero 
WHERE hero.id = ?
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine [cached since 0.0005488s ago] (8,)
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine SELECT hero.id, hero.name, hero.secret_name, hero.age, hero.team_id 
FROM hero 
WHERE hero.id = ?
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine [cached since 0.0007544s ago] (9,)
Created hero: name='Deadpond' team_id=None secret_name='Dive Wilson' id=7 age=None
Created hero: name='Rusty-Man' team_id=None secret_name='Tommy Sharp' id=8 age=48
Created hero: name='Spider-Boy' team_id=None secret_name='Pedro Parqueador' id=9 age=None
2022-05-19 10:57:57,551 INFO sqlalchemy.engine.Engine COMMIT
2022-05-19 10:57:57,552 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-05-19 10:57:57,552 INFO sqlalchemy.engine.Engine SELECT hero.id, hero.name, hero.secret_name, hero.age, hero.team_id 
FROM hero 
WHERE hero.id = ?
2022-05-19 10:57:57,552 INFO sqlalchemy.engine.Engine [cached since 0.001206s ago] (9,)
Updated hero: name='Spider-Boy' team_id=None secret_name='Pedro Parqueador' id=9 age=None
2022-05-19 10:57:57,552 INFO sqlalchemy.engine.Engine INSERT INTO team (name, headquarters) VALUES (?, ?)
2022-05-19 10:57:57,552 INFO sqlalchemy.engine.Engine [generated in 0.00006s] ('Wakaland', 'Wakaland Capital City')
2022-05-19 10:57:57,553 INFO sqlalchemy.engine.Engine COMMIT
2022-05-19 10:57:57,553 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-05-19 10:57:57,554 INFO sqlalchemy.engine.Engine SELECT team.id, team.name, team.headquarters 
FROM team 
WHERE team.id = ?
2022-05-19 10:57:57,554 INFO sqlalchemy.engine.Engine [generated in 0.00006s] (3,)
Team Wakaland: name='Wakaland' headquarters='Wakaland Capital City' id=3
2022-05-19 10:57:57,554 INFO sqlalchemy.engine.Engine ROLLBACK
Traceback (most recent call last):
  File "/Users/marcel/test_sqlmodel/test.py", line 104, in <module>
    main()
  File "/Users/marcel/test_sqlmodel/test.py", line 98, in main
    create_heroes()
  File "/Users/marcel/test_sqlmodel/test.py", line 83, in create_heroes
    team_preventers.heroes.append(hero_tarantula)
AttributeError: 'Team' object has no attribute 'heroes'

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.6

Python Version

3.10.4

Additional Context

No response

[mkrd]

@tiangolo I Checked it with python 3.10, 3.9 and 3.8, all throwing the same error. I always use a clean new venv created with poetry, so there are no conflicts with other packages.

The packages that get installed are:

• typing-extensions (4.2.0)
• pydantic (1.9.0)
• sqlalchemy (1.4.36)
• sqlalchemy2-stubs (0.0.2a22)
• sqlmodel (0.0.6)

Maybe there are some breaking changes in sqlalchemy or pydantic, so we need to lock down the version requirements more tightly?

[byrman]

Check #315.

[tiangolo]

Thanks for the report @mkrd and for the help @byrman!

It seems this was solved by @byrman in #322.

The fix is available in SQLModel 0.0.7 🚀

[github-actions]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.