创建和更新关系¶
现在让我们看看如何使用这些新的关系属性创建带关系的数据。✨
使用字段创建实例¶
让我们检查一下我们以前用来创建英雄和团队的代码
# Code above omitted 👆
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")
session.add(team_preventers)
session.add(team_z_force)
session.commit()
hero_deadpond = Hero(
name="Deadpond", secret_name="Dive Wilson", team_id=team_z_force.id
)
hero_rusty_man = Hero(
name="Rusty-Man",
secret_name="Tommy Sharp",
age=48,
team_id=team_preventers.id,
)
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)
# Code below omitted 👇
👀 完整文件预览
from sqlmodel import Field, Session, SQLModel, create_engine
class Team(SQLModel, table=True):
id: int | None = Field(default=None, primary_key=True)
name: str = Field(index=True)
headquarters: str
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")
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")
session.add(team_preventers)
session.add(team_z_force)
session.commit()
hero_deadpond = Hero(
name="Deadpond", secret_name="Dive Wilson", team_id=team_z_force.id
)
hero_rusty_man = Hero(
name="Rusty-Man",
secret_name="Tommy Sharp",
age=48,
team_id=team_preventers.id,
)
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)
def main():
create_db_and_tables()
create_heroes()
if __name__ == "__main__":
main()
🤓 其他版本和变体
from typing import Optional
from sqlmodel import Field, 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
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")
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")
session.add(team_preventers)
session.add(team_z_force)
session.commit()
hero_deadpond = Hero(
name="Deadpond", secret_name="Dive Wilson", team_id=team_z_force.id
)
hero_rusty_man = Hero(
name="Rusty-Man",
secret_name="Tommy Sharp",
age=48,
team_id=team_preventers.id,
)
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)
def main():
create_db_and_tables()
create_heroes()
if __name__ == "__main__":
main()
这里有几件事需要注意。
首先，我们创建了一些Team实例对象。我们想在创建Hero实例时，在team_id字段中使用这些团队的ID。
但是模型实例在我们将它们add并commit到会话之前，没有数据库生成的ID。在此之前，它们只是None，我们想使用实际的ID。
所以，我们必须先add它们并commit会话，然后才能开始创建Hero实例，以便能够使用它们的ID。
然后，我们在创建Hero实例时使用这些ID。我们将新英雄add到会话中，然后commit它们。
所以，我们提交了两次。而且我们必须记住先add一些东西，然后commit，并且所有这些都必须按正确的顺序完成，否则我们可能会使用一个当前为None的team.id，因为它还没有被保存。
这是这些关系属性可以提供帮助的第一个领域。🤓
使用关系属性创建实例¶
现在让我们完成所有这些，但这次使用新的、闪亮亮的Relationship属性
# Code above omitted 👆
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)
# Code below omitted 👇
👀 完整文件预览
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine
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")
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")
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()
def main():
create_db_and_tables()
create_heroes()
if __name__ == "__main__":
main()
🤓 其他版本和变体
from typing import 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()
def main():
create_db_and_tables()
create_heroes()
if __name__ == "__main__":
main()
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()
def main():
create_db_and_tables()
create_heroes()
if __name__ == "__main__":
main()
现在我们可以创建Team实例，并在创建Hero实例时将它们直接传递给新的team参数，例如team=team_preventers而不是team_id=team_preventers.id。
多亏了SQLAlchemy及其底层工作原理，这些团队甚至不需要拥有ID，但由于我们将整个对象分配给每个英雄，这些团队将自动在数据库中创建，自动ID将生成，并设置在每个相应英雄行的team_id列中。
事实上，现在我们甚至不需要使用session.add(team)将团队显式地放入会话中，因为这些Team实例已经与我们确实add到会话的英雄相关联。
SQLAlchemy知道它还必须在下次提交时包含这些团队，才能正确保存英雄。
然后，正如你所看到的，我们只需要执行一次commit()。
分配关系¶
正如我们可以将带有team.id的整数分配给hero.team_id一样，我们也可以将Team实例分配给hero.team
# Code above omitted 👆
def create_heroes():
with Session(engine) as session:
# Code here omitted 👈
hero_spider_boy.team = team_preventers
session.add(hero_spider_boy)
session.commit()
session.refresh(hero_spider_boy)
print("Updated hero:", hero_spider_boy)
# Code below omitted 👇
👀 完整文件预览
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine
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")
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")
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)
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()
🤓 其他版本和变体
from typing import 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()
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()
创建包含英雄的团队¶
之前，我们创建了一些Team实例，并在创建Hero实例时将它们传递给team=参数。
我们也可以先创建Hero实例，然后在创建Team实例时将它们传递给接受列表的heroes=参数
# Code above omitted 👆
def create_heroes():
with Session(engine) as session:
# Code here omitted 👈
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)
# Code below omitted 👇
👀 完整文件预览
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine
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")
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")
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)
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()
🤓 其他版本和变体
from typing import 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()
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()
这里我们首先创建两个英雄，黑狮和苏尔-E公主，然后将它们传递给heroes参数。
请注意，与之前一样，我们只需要将Team实例add到会话中，因为英雄与它连接，当commit时它们也会自动保存。
在多对一关系中包含关系对象¶
我们之前说过，这是一个多对一关系，因为可以有很多英雄属于一个团队。
我们还可以使用这些关系属性在多方连接数据。
由于属性team.heroes的行为类似于列表，我们可以简单地向其添加元素。
让我们创建更多英雄并将它们添加到team_preventers.heroes列表属性中
# Code above omitted 👆
def create_heroes():
with Session(engine) as session:
# Code here omitted 👈
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)
# Code below omitted 👇
👀 完整文件预览
from sqlmodel import Field, Relationship, Session, SQLModel, create_engine
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")
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")
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)
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()
🤓 其他版本和变体
from typing import 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()
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()
属性team_preventers.heroes的行为类似于列表。但它是一种特殊类型的列表，因为当我们修改它并向其中添加英雄时，SQLModel（实际上是SQLAlchemy）会跟踪在数据库中需要进行的更改。
然后我们将团队add()到会话中并commit()。
与之前一样，我们甚至不需要将独立的英雄add()到会话中，因为它们与团队连接。
回顾¶
我们可以使用常见的Python对象和属性通过这些关系属性创建和更新数据连接。😎
接下来我们将看到如何使用这些关系属性读取连接数据。🤝