✨ Add support for cascade delete relationships: cascade_delete, `on…

…delete`, and `passive_deletes` (#983) Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>
fastapi · Jul 21, 2024 · 86ab09f · 86ab09f
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diff --git a/docs/tutorial/relationship-attributes/cascade-delete-relationships.md b/docs/tutorial/relationship-attributes/cascade-delete-relationships.md
diff --git a/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/__init__.py b/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/__init__.py
diff --git a/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001.py b/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001.py
@@ -0,0 +1,110 @@
+from typing import List, Optional
+
+from sqlmodel import Field, Relationship, Session, SQLModel, create_engine, select
+
+
+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", cascade_delete=True)
+
+
+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", ondelete="CASCADE"
+    )
+    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)
+
+
+def delete_team():
+    with Session(engine) as session:
+        statement = select(Team).where(Team.name == "Wakaland")
+        team = session.exec(statement).one()
+        session.delete(team)
+        session.commit()
+        print("Deleted team:", team)
+
+
+def select_deleted_heroes():
+    with Session(engine) as session:
+        statement = select(Hero).where(Hero.name == "Black Lion")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Black Lion not found:", hero)
+
+        statement = select(Hero).where(Hero.name == "Princess Sure-E")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Princess Sure-E not found:", hero)
+
+
+def main():
+    create_db_and_tables()
+    create_heroes()
+    delete_team()
+    select_deleted_heroes()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001_py310.py b/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001_py310.py
@@ -0,0 +1,106 @@
+from sqlmodel import Field, Relationship, Session, SQLModel, create_engine, select
+
+
+class Team(SQLModel, table=True):
+    id: int | None = Field(default=None, primary_key=True)
+    name: str = Field(index=True)
+    headquarters: str
+
+    heroes: list["Hero"] = Relationship(back_populates="team", cascade_delete=True)
+
+
+class Hero(SQLModel, table=True):
+    id: int | None = Field(default=None, primary_key=True)
+    name: str = Field(index=True)
+    secret_name: str
+    age: int | None = Field(default=None, index=True)
+
+    team_id: int | None = Field(default=None, foreign_key="team.id", ondelete="CASCADE")
+    team: Team | None = 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)
+
+
+def delete_team():
+    with Session(engine) as session:
+        statement = select(Team).where(Team.name == "Wakaland")
+        team = session.exec(statement).one()
+        session.delete(team)
+        session.commit()
+        print("Deleted team:", team)
+
+
+def select_deleted_heroes():
+    with Session(engine) as session:
+        statement = select(Hero).where(Hero.name == "Black Lion")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Black Lion not found:", hero)
+
+        statement = select(Hero).where(Hero.name == "Princess Sure-E")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Princess Sure-E not found:", hero)
+
+
+def main():
+    create_db_and_tables()
+    create_heroes()
+    delete_team()
+    select_deleted_heroes()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001_py39.py b/docs_src/tutorial/relationship_attributes/cascade_delete_relationships/tutorial001_py39.py
@@ -0,0 +1,110 @@
+from typing import Optional
+
+from sqlmodel import Field, Relationship, Session, SQLModel, create_engine, select
+
+
+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", cascade_delete=True)
+
+
+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", ondelete="CASCADE"
+    )
+    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)
+
+
+def delete_team():
+    with Session(engine) as session:
+        statement = select(Team).where(Team.name == "Wakaland")
+        team = session.exec(statement).one()
+        session.delete(team)
+        session.commit()
+        print("Deleted team:", team)
+
+
+def select_deleted_heroes():
+    with Session(engine) as session:
+        statement = select(Hero).where(Hero.name == "Black Lion")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Black Lion not found:", hero)
+
+        statement = select(Hero).where(Hero.name == "Princess Sure-E")
+        result = session.exec(statement)
+        hero = result.first()
+        print("Princess Sure-E not found:", hero)
+
+
+def main():
+    create_db_and_tables()
+    create_heroes()
+    delete_team()
+    select_deleted_heroes()
+
+
+if __name__ == "__main__":
+    main()