关系 back_populates¶
现在你已经知道如何使用 关系属性 来操作数据库中连接的数据了！🎉
接下来，我们稍微回顾一下之前定义 Relationship() 属性的方式，并澄清一下 back_populates 参数的含义。🤓
带有 back_populates 的关系¶
那么，Relationship() 中的 back_populates 参数到底是什么呢？
它的值是一个字符串，表示**另一个**模型类中属性的名称。
这告诉 SQLModel，如果当前模型中发生了变化，它应该同步更新另一个模型中的对应属性，而且即使在提交（commit）之前，它也会立刻生效（而不需要强制刷新数据）。
让我们通过一个例子来更好地理解这一点。
不完整的关系¶
首先，我们通过不使用 back_populates 来写一个**不完整**的版本，看看它是如何工作的：
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()
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()
# 代码下面部分省略 👇
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()
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()
# 代码下面部分省略 👇
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()
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()
# 代码下面部分省略 👇
👀 完整文件预览
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
读取数据对象¶
现在，我们将获取 Spider-Boy 英雄，并独立地获取 Preventers 队伍，使用两个 select 语句。
如你所知，如何执行这两个操作，我就不再分开讲解 select 语句、results 等内容了。我们直接使用更简洁的形式，通过一个调用来完成：
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
# 代码下面部分省略 👇
👀 完整文件预览
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
Tip
在编写自己的代码时，这可能是你最常用的风格，因为它更加简洁、方便，并且你依然能享受自动补全和内联错误提示的所有优势。
打印数据¶
现在，让我们打印当前的 Spider-Boy，当前的 Preventers 队伍，特别是当前 Preventers 英雄列表：
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
# 代码下面部分省略 👇
👀 完整文件预览
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
到目前为止，一切正常。😊
特别是，打印 preventers_team.heroes 的结果是：
Preventers 队伍英雄：[
Hero(name='Rusty-Man', age=48, id=2, secret_name='Tommy Sharp', team_id=2),
Hero(name='Spider-Boy', age=None, id=3, secret_name='Pedro Parqueador', team_id=2),
Hero(name='Tarantula', age=32, id=6, secret_name='Natalia Roman-on', team_id=2),
Hero(name='Dr. Weird', age=36, id=7, secret_name='Steve Weird', team_id=2),
Hero(name='Captain North America', age=93, id=8, secret_name='Esteban Rogelios', team_id=2)
]
注意，我们在这里看到了 Spider-Boy 。
提交前更新对象¶
现在让我们更新 Spider-Boy，通过将 hero_spider_boy.team = None 来将他从队伍中移除，然后再打印这个对象：
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
👀 完整文件预览
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
首先需要注意的是，我们**还没有提交**英雄对象，因此访问英雄列表不会触发自动刷新。
但在我们的代码中，恰恰在这个时刻，我们已经声明 Spider-Boy 不再是 Preventers 队伍的一员了。🔥
Tip
我们以后可以通过不提交 session 来撤销这一更改，但这不是我们在这里关注的内容。
在此时的代码中，在内存中，代码预期 Preventers 不再包括 Spider-Boy。
打印没有队伍的 hero_spider_boy 的输出是：
没有队伍的 Spider-Boy: name='Spider-Boy' age=None id=3 secret_name='Pedro Parqueador' team_id=2 team=None
很酷，队伍已经被设置为 None，team_id 属性仍然保留队伍 ID，直到我们保存它。但没关系，因为我们现在主要是在操作 关系属性 和对象。✅
但是现在，当我们打印 preventers_team.heroes 时会发生什么？
Preventers 队伍英雄（更新后）: [
Hero(name='Rusty-Man', age=48, id=2, secret_name='Tommy Sharp', team_id=2),
Hero(name='Spider-Boy', age=None, id=3, secret_name='Pedro Parqueador', team_id=2, team=None),
Hero(name='Tarantula', age=32, id=6, secret_name='Natalia Roman-on', team_id=2),
Hero(name='Dr. Weird', age=36, id=7, secret_name='Steve Weird', team_id=2),
Hero(name='Captain North America', age=93, id=8, secret_name='Esteban Rogelios', team_id=2)
]
哦，不！😱 Spider-Boy 仍然出现在列表中！
提交并打印¶
现在，如果我们提交更改并再次打印：
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
# 代码下面部分省略 👇
👀 完整文件预览
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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()
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()
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
在我们提交后访问 preventers_team.heroes 时，会触发数据刷新，所以我们得到了最新的列表， Spider-Boy 被移除了，结果就正常了：
INFO Engine SELECT hero.id AS hero_id, hero.name AS hero_name, hero.secret_name AS hero_secret_name, hero.age AS hero_age, hero.team_id AS hero_team_id
FROM hero
WHERE ? = hero.team_id
2021-08-13 11:15:24,658 INFO sqlalchemy.engine.Engine [cached since 0.1924s ago] (2,)
Preventers Team Heroes after commit: [
Hero(name='Rusty-Man', age=48, id=2, secret_name='Tommy Sharp', team_id=2),
Hero(name='Tarantula', age=32, id=6, secret_name='Natalia Roman-on', team_id=2),
Hero(name='Dr. Weird', age=36, id=7, secret_name='Steve Weird', team_id=2),
Hero(name='Captain North America', age=93, id=8, secret_name='Esteban Rogelios', team_id=2)
]
提交后没有 Spider-Boy ，所以一切正常。😊
不过，在之前的那一部分，我们依然存在不一致的情况。
如果我们在提交前就使用了对象，可能会遇到错误。😔
让我们来修复这个问题。🤓
使用 back_populates 修复¶
这就是 back_populates 的作用。✨
让我们将其添加回来：
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")
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")
# 代码下面部分省略 👇
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")
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")
# 代码下面部分省略 👇
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")
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")
# 代码下面部分省略 👇
/// 详细信息 | 👀 完整文件预览
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
///
然后我们可以保持其余代码不变：
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
# 代码上面部分省略 👆
def update_heroes():
with Session(engine) as session:
# 这里的代码省略 👈
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
# 代码下面部分省略 👇
👀 完整文件预览
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
Tip
这是我们之前将 hero_spider_boy.team 设置为 None 但*尚未提交*该更改的同一部分。
也就是之前导致问题的部分。
回顾结果¶
这次， SQLModel （实际上是 SQLAlchemy）能够注意到更改，并 自动更新团队中的英雄列表 ，即使我们还没有提交。
第二次打印将输出：
Preventers Team Heroes again: [
Hero(name='Rusty-Man', age=48, id=2, secret_name='Tommy Sharp', team_id=2),
Hero(name='Tarantula', age=32, id=6, secret_name='Natalia Roman-on', team_id=2),
Hero(name='Dr. Weird', age=36, id=7, secret_name='Steve Weird', team_id=2),
Hero(name='Captain North America', age=93, id=8, secret_name='Esteban Rogelios', team_id=2)
]
请注意，现在 Spider-Boy 不再出现在列表中，我们通过 back_populates 修复了这一点！🎉
back_populates 的价值¶
现在你知道了 back_populates 的作用，让我们再次回顾它的具体价值。
代码其实很简单，它只是一个字符串，但可能会让人困惑的是，究竟应该在这里使用什么字符串：
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")
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")
# 代码下面部分省略 👇
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")
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")
# 代码下面部分省略 👇
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")
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")
# 代码下面部分省略 👇
👀 完整文件预览
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
back_populates 中的字符串是指在 另一个 模型中，将引用 当前 模型的属性。
因此，在 Team 类中，我们有一个属性 heroes，并使用 Relationship(back_populates="team") 来声明它。
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
👀 完整文件预览
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
back_populates="team" 中的字符串指的是 Hero 类（另一个类）中的 team 属性。
在 Hero 类中，我们声明了一个属性 team，并使用 Relationship(back_populates="heroes") 来声明它。
因此，字符串 "heroes" 指的是 Team 类中的 heroes 属性。
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
# 代码下面部分省略 👇
👀 完整文件预览
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
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")
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 select_heroes():
with Session(engine) as session:
statement = select(Team).where(Team.name == "Preventers")
result = session.exec(statement)
team_preventers = result.one()
print("Preventers heroes:", team_preventers.heroes)
def update_heroes():
with Session(engine) as session:
hero_spider_boy = session.exec(
select(Hero).where(Hero.name == "Spider-Boy")
).one()
preventers_team = session.exec(
select(Team).where(Team.name == "Preventers")
).one()
print("Hero Spider-Boy:", hero_spider_boy)
print("Preventers Team:", preventers_team)
print("Preventers Team Heroes:", preventers_team.heroes)
hero_spider_boy.team = None
print("Spider-Boy without team:", hero_spider_boy)
print("Preventers Team Heroes again:", preventers_team.heroes)
session.add(hero_spider_boy)
session.commit()
print("After committing")
session.refresh(hero_spider_boy)
print("Spider-Boy after commit:", hero_spider_boy)
print("Preventers Team Heroes after commit:", preventers_team.heroes)
def main():
create_db_and_tables()
create_heroes()
select_heroes()
update_heroes()
if __name__ == "__main__":
main()
Tip
每个 关系属性 都通过 back_populates 指向另一个模型中的对应属性。
尽管代码很简单，但理解时可能会让人困惑 😵，因为同一行代码涉及到了多个模型的概念：
- 仅仅因为它位于 当前 模型中，这行代码与当前模型相关。
- 属性的名称与 另一个 模型相关。
- 类型注解与 另一个 模型相关。
back_populates指向的是 另一个 模型中的属性，而这个属性指向的是 当前 模型。
记住 back_populates 的一个心理技巧¶
你可以使用的一个心理技巧是，back_populates 中的字符串始终是关于你正在编辑的当前模型类的。🤓
因此，如果你在 Hero 类中，back_populates 中的任何关系属性，无论它连接到 任何 其他表（比如 Team、Weapon、Powers 等），都会始终指向这个相同的类。
所以，back_populates 的值很可能是 "hero" 或 "heroes"。
# 代码上面部分省略 👆
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")
weapon_id: int | None = Field(default=None, foreign_key="weapon.id")
weapon: Weapon | None = Relationship(back_populates="hero")
powers: list[Power] = Relationship(back_populates="hero")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
weapon_id: Optional[int] = Field(default=None, foreign_key="weapon.id")
weapon: Optional[Weapon] = Relationship(back_populates="hero")
powers: list[Power] = Relationship(back_populates="hero")
# 代码下面部分省略 👇
# 代码上面部分省略 👆
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")
weapon_id: Optional[int] = Field(default=None, foreign_key="weapon.id")
weapon: Optional[Weapon] = Relationship(back_populates="hero")
powers: List[Power] = Relationship(back_populates="hero")
# 代码下面部分省略 👇
👀 完整文件预览
from sqlmodel import Field, Relationship, SQLModel, create_engine
class Weapon(SQLModel, table=True):
id: int | None = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero: "Hero" = Relationship(back_populates="weapon")
class Power(SQLModel, table=True):
id: int | None = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero_id: int = Field(foreign_key="hero.id")
hero: "Hero" = Relationship(back_populates="powers")
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")
weapon_id: int | None = Field(default=None, foreign_key="weapon.id")
weapon: Weapon | None = Relationship(back_populates="hero")
powers: list[Power] = Relationship(back_populates="hero")
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 main():
create_db_and_tables()
if __name__ == "__main__":
main()
from typing import Optional
from sqlmodel import Field, Relationship, SQLModel, create_engine
class Weapon(SQLModel, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero: "Hero" = Relationship(back_populates="weapon")
class Power(SQLModel, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero_id: int = Field(foreign_key="hero.id")
hero: "Hero" = Relationship(back_populates="powers")
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")
weapon_id: Optional[int] = Field(default=None, foreign_key="weapon.id")
weapon: Optional[Weapon] = Relationship(back_populates="hero")
powers: list[Power] = Relationship(back_populates="hero")
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 main():
create_db_and_tables()
if __name__ == "__main__":
main()
from typing import List, Optional
from sqlmodel import Field, Relationship, SQLModel, create_engine
class Weapon(SQLModel, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero: "Hero" = Relationship(back_populates="weapon")
class Power(SQLModel, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
name: str = Field(index=True)
hero_id: int = Field(foreign_key="hero.id")
hero: "Hero" = Relationship(back_populates="powers")
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")
weapon_id: Optional[int] = Field(default=None, foreign_key="weapon.id")
weapon: Optional[Weapon] = Relationship(back_populates="hero")
powers: List[Power] = Relationship(back_populates="hero")
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 main():
create_db_and_tables()
if __name__ == "__main__":
main()