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sqlmodel ondelete cascade

serge kalaga answered on May 18, 2023 Popularity 9/10 Helpfulness 4/10

answer sqlmodel ondelete cascade

related ondelete cascade

sqlmodel ondelete cascade

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from typing import List, Optional
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine


class Hero(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    tests: List["Test"] = Relationship(
        sa_relationship_kwargs={"cascade": "delete"}
        # Doesn't work vvv
        # sa_relationship_kwargs={"cascade": "all, delete"}
    )


class Test(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    hero_id: Optional[int] = Field(default=None, foreign_key="hero.id")


engine = create_engine("sqlite:///", echo=True)


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


def create_heroes():
    hero = Hero(name="Deadpond", secret_name="Dive Wilson")
    t1 = Test()
    t2 = Test()
    hero.tests = [t1, t2]

    with Session(engine) as session:
        session.add(hero)
        session.commit()
        session.query(Hero).delete()
        session.commit()
        heroes = session.query(Hero).all()
        print(heroes)
        assert len(heroes) == 0
        tests = session.query(Test).all()
        print(tests)
        assert len(tests) == 0


def main():  #
    create_db_and_tables()  #
    create_heroes()  #


if __name__ == "__main__":  #
    main()

"""
2022-01-13 15:37:54,273 INFO sqlalchemy.engine.Engine DELETE FROM hero
2022-01-13 15:37:54,273 INFO sqlalchemy.engine.Engine [generated in 0.00006s] ()
2022-01-13 15:37:54,273 INFO sqlalchemy.engine.Engine COMMIT
2022-01-13 15:37:54,273 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2022-01-13 15:37:54,274 INFO sqlalchemy.engine.Engine SELECT hero.id AS hero_id 
FROM hero
2022-01-13 15:37:54,274 INFO sqlalchemy.engine.Engine [generated in 0.00006s] ()
[]
2022-01-13 15:37:54,275 INFO sqlalchemy.engine.Engine SELECT test.id AS test_id, test.hero_id AS test_hero_id 
FROM test
2022-01-13 15:37:54,275 INFO sqlalchemy.engine.Engine [generated in 0.00006s] ()
[]
2022-01-13 15:37:54,275 INFO sqlalchemy.engine.Engine ROLLBACK
"""

Popularity 9/10 Helpfulness 4/10 Language python

Source: Grepper

Tags: cascade python

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Contributed on Sep 20 2023

serge kalaga

0 Answers Avg Quality 2/10

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ondelete cascade

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When the referenced object is deleted, all objects that have 
a foreign key to it will also be deleted.

For example, let's say we have an Author named "John" and two 
books associated with him. If we delete the "John" Author object, 
the two Book objects associated with "John" will also be 
deleted automatically.

from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)

Popularity 9/10 Helpfulness 3/10 Language python

Source: Grepper

Tags: cascade

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Contributed on May 18 2023

Manish Bhusal

0 Answers Avg Quality 2/10

sqlmodel ondelete cascade

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