58 lines
1.6 KiB
Python
58 lines
1.6 KiB
Python
"""
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Demonstrate relationships and joined reads using SQLModel with generic kit.
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Run: uv run python examples/03_relationships.py
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"""
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from typing import List, Optional
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from sqlalchemy.orm import selectinload
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from sqlmodel import SQLModel, select, Field, Relationship
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from sqlmodel_pg_kit import create_all
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from sqlmodel_pg_kit.db import get_session
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class Team(SQLModel, table=True):
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id: Optional[int] = Field(default=None, primary_key=True)
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name: str = Field(index=True)
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heroes: List["Hero"] = Relationship(back_populates="team")
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class Hero(SQLModel, table=True):
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id: Optional[int] = Field(default=None, primary_key=True)
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name: str = Field(index=True)
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age: Optional[int] = None
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team_id: Optional[int] = Field(default=None, foreign_key="team.id")
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team: Optional[Team] = Relationship(back_populates="heroes")
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def main():
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create_all()
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with get_session() as s:
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# Clean
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s.execute(Hero.__table__.delete())
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s.execute(Team.__table__.delete())
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s.commit()
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# Create Team and Heroes
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t = Team(name="Avengers")
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s.add(t)
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s.commit()
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s.refresh(t)
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h1 = Hero(name="Thor", age=1500, team_id=t.id)
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h2 = Hero(name="Hulk", age=49, team_id=t.id)
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s.add(h1)
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s.add(h2)
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s.commit()
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# Query heroes and eager-load team via selectinload
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stmt = select(Hero).options(selectinload(Hero.team)).order_by(Hero.id.asc())
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heroes: List[Hero] = s.exec(stmt).all()
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print([(h.name, h.team.name if h.team else None) for h in heroes])
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if __name__ == "__main__":
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main()
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