3. 一对一关系

python
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from typing import Optional

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


class Card(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    card_id: str = Field(index=True)
    card_user: str
    tel: str

    detail: Optional["CardDetail"] = Relationship(
        back_populates="card",
        sa_relationship_kwargs={"uselist": False},
    )


class CardDetail(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    mail: str = Field(index=True)
    city: str
    address: str
    card_id: int | None = Field(default=None, foreign_key="card.id")

    card: Optional[Card] = Relationship(
        back_populates="detail",
        sa_relationship_kwargs={"uselist": False},
        )


def test():
    sqlite_file_name = "database.db"
    sqlite_url = f"sqlite:///{sqlite_file_name}"
    engine = create_engine(sqlite_url, echo=False)
    SQLModel.metadata.drop_all(engine)
    SQLModel.metadata.create_all(engine)

    with Session(engine) as session:
        card1 = Card(card_id="11111111", card_user="Lee", tel="111")
        card2 = Card(card_id="22222222", card_user="John", tel="222")

        card_detail1 = CardDetail(
            mail="Lee@163.com",
            city="Shanghai",
            address="No. 1",
            card=card1,
        )
        card_detail2 = CardDetail(
            mail="john@163.com",
            city="Beijing",
            address="No. 1",
            card=card2,
        )
        session.add(card_detail1)
        session.add(card_detail2)
        session.commit()

        session.refresh(card1)
        session.refresh(card2)
        session.refresh(card_detail1)
        session.refresh(card_detail2)

        print("Card1:", card1)
        print("Card1 detail:", card1.detail)
        print("Card2:", card2)
        print("Card2 detail:", card2.detail)


if __name__ == "__main__":
    test()

一对一关系中需要注意设置 sa_relationship_kwargs={"uselist": False},