Skip to content

SQL（關聯式）資料庫

🌐 AI 與人類共同完成的翻譯

此翻譯由人類指導的 AI 完成。🤝

可能會有對原意的誤解，或讀起來不自然等問題。🤖

你可以透過協助我們更好地引導 AI LLM來改進此翻譯。

英文版

FastAPI 不強制你使用 SQL（關聯式）資料庫。你可以使用任何你想要的資料庫。

這裡我們會用 SQLModel 作為範例。

SQLModel 建立在 SQLAlchemy 與 Pydantic 之上。它由 FastAPI 的作者開發，非常適合需要使用 SQL 資料庫的 FastAPI 應用。

提示

你可以使用任何你想用的 SQL 或 NoSQL 資料庫函式庫（有時稱為 "ORMs"），FastAPI 不會強迫你使用特定工具。😎

因為 SQLModel 建立在 SQLAlchemy 之上，你可以輕鬆使用 SQLAlchemy 所支援的任何資料庫（因此 SQLModel 也支援），例如：

  • PostgreSQL
  • MySQL
  • SQLite
  • Oracle
  • Microsoft SQL Server，等等。

在這個範例中，我們會使用 SQLite，因為它只用到單一檔案，而且 Python 內建支援。你可以直接複製這個範例並原樣執行。

之後，在你的正式環境應用中，你可能會想使用像 PostgreSQL 這類的資料庫伺服器。

提示

有一個包含 FastAPI 與 PostgreSQL 的官方專案腳手架，還有前端與更多工具：https://github.com/fastapi/full-stack-fastapi-template

這是一份非常簡短的教學，如果你想更全面學習資料庫、SQL，或更進階的功能，請參考 SQLModel 文件。

安裝 SQLModel

首先，請先建立你的虛擬環境、啟用它，然後安裝 sqlmodel：

$ pip install sqlmodel
---> 100%

建立只有單一模型的應用

我們先用單一 SQLModel 模型建立這個應用的最簡版。

接著我們會在下方用多個模型來提升安全性與彈性。🤓

建立模型

匯入 SQLModel 並建立一個資料庫模型：

from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

Hero 類別與 Pydantic 模型非常相似（事實上，在底層它就是一個 Pydantic 模型）。

有幾點差異：

  • table=True 告訴 SQLModel 這是一個「資料表模型」（table model），它應該代表 SQL 資料庫中的一個資料表，而不僅僅是「資料模型」（就像一般的 Pydantic 類別）。

  • Field(primary_key=True) 告訴 SQLModel，id 是 SQL 資料庫中的「主鍵」。 （你可以在 SQLModel 文件中進一步了解 SQL 主鍵）

    注意：我們在主鍵欄位使用 int | None，這樣在 Python 程式碼中我們可以「在沒有 id 的情況下建立物件」（id=None），假設資料庫在儲存時會「自動產生」。SQLModel 瞭解資料庫會提供 id，並且在資料庫綱要中「將該欄位定義為非空的 INTEGER」。詳情請見 SQLModel 文件：主鍵。

  • Field(index=True) 告訴 SQLModel 應為此欄位建立「SQL 索引」，以便在用此欄位過濾讀取資料時更快查詢。

    SQLModel 會知道宣告為 str 的欄位在 SQL 中會是 TEXT（或 VARCHAR，依資料庫而定）。

建立引擎

SQLModel 的 engine（底層實際上是 SQLAlchemy 的 engine）是用來「維護與資料庫連線」的東西。

你的程式中應該只有「單一 engine 物件」來連到同一個資料庫。

# Code above omitted 👆

sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

使用 check_same_thread=False 允許 FastAPI 在不同執行緒中使用同一個 SQLite 資料庫。這是必要的，因為「單一請求」可能會使用「多個執行緒」（例如在依賴項中）。

別擔心，依照我們的程式結構，稍後我們會確保「每個請求只使用單一 SQLModel 的 session」，這其實就是 check_same_thread 想要達成的事。

建立資料表

接著我們新增一個函式，使用 SQLModel.metadata.create_all(engine) 為所有「資料表模型」建立資料表。

# Code above omitted 👆

def create_db_and_tables():
    SQLModel.metadata.create_all(engine)

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

建立 Session 依賴

「Session」會在記憶體中保存物件並追蹤資料需要的任何變更，然後透過「engine」與資料庫溝通。

我們會用 yield 建立一個 FastAPI 的「依賴」，為每個請求提供一個新的 Session。這可確保每個請求只使用單一的 session。🤓

接著我們建立一個 Annotated 的依賴 SessionDep，讓後續使用這個依賴的程式碼更簡潔。

# Code above omitted 👆

def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

在啟動時建立資料表

我們會在應用啟動時建立資料庫的資料表。

# Code above omitted 👆

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

這裡我們在應用的啟動事件中建立資料表。

在正式環境中，你大概會在啟動應用前使用遷移腳本來處理。🤓

提示

SQLModel 之後會提供包裝 Alembic 的遷移工具，但目前你可以直接使用 Alembic。

建立 Hero

因為每個 SQLModel 模型同時也是一個 Pydantic 模型，你可以在「型別標註」中像使用 Pydantic 模型一樣使用它。

例如，如果你宣告一個參數型別為 Hero，它會從「JSON body」中讀取。

同樣地，你也可以將它宣告為函式的「回傳型別」，然後在自動產生的 API 文件 UI 中就會顯示其資料結構。

# Code above omitted 👆

@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

這裡我們使用 SessionDep 依賴（即一個 Session），把新的 Hero 加入 Session 實例，提交變更到資料庫，刷新 hero 的資料，然後回傳它。

讀取多個 Hero

我們可以用 select() 從資料庫「讀取」多個 Hero。可以加入 limit 與 offset 來分頁。

# Code above omitted 👆

@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

讀取單一 Hero

我們可以「讀取」單一的 Hero。

# Code above omitted 👆

@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

刪除 Hero

我們也可以「刪除」一個 Hero。

# Code above omitted 👆

@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]

app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: SessionDep) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: SessionDep) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}")
def read_hero(hero_id: int, session: Session = Depends(get_session)) -> Hero:
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

執行應用

你可以執行應用：

$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

然後前往 /docs 的 UI，你會看到 FastAPI 使用這些模型來「文件化」API，也會用它們來「序列化」與「驗證」資料。

用多個模型更新應用

現在我們稍微「重構」一下這個應用，以提升「安全性」與「彈性」。

如果你檢查前一版的應用，在 UI 中你會看到，到目前為止它讓用戶端自己決定要建立的 Hero 的 id。😱

我們不該允許這樣，因為他們可能會覆蓋資料庫中我們已分配的 id。決定 id 應該由「後端」或「資料庫」來做，「不是用戶端」。

另外，我們為 hero 建立了 secret_name，但目前我們在各處都把它回傳出去，這一點都不「保密」... 😅

我們會透過加入一些「額外模型」來修正這些問題。這正是 SQLModel 大放異彩的地方。✨

建立多個模型

在 SQLModel 中，任何設了 table=True 的模型類別都是「資料表模型」。

而沒有設 table=True 的模型類別就是「資料模型」，這些其實就是 Pydantic 模型（只有一點小增強）。🤓

使用 SQLModel，我們可以利用「繼承」來「避免重複」在各種情況下一再宣告所有欄位。

HeroBase - 基底類別

先從 HeroBase 模型開始，它包含所有模型「共享」的欄位：

  • name
  • age
# Code above omitted 👆

class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

Hero - 資料表模型

接著建立 Hero，也就是實際的「資料表模型」，它包含不一定會出現在其他模型中的「額外欄位」：

  • id
  • secret_name

因為 Hero 繼承自 HeroBase，它「也」擁有 HeroBase 中宣告的「欄位」，因此 Hero 的完整欄位為：

  • id
  • name
  • age
  • secret_name
# Code above omitted 👆

class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

HeroPublic - 公開的資料模型

接下來建立 HeroPublic 模型，它是要「回傳」給 API 用戶端的模型。

它擁有與 HeroBase 相同的欄位，因此不會包含 secret_name。

終於，我們英雄的真實身分受保護了！🥷

它也重新宣告了 id: int。這麼做是與 API 用戶端訂立一個「契約」，讓他們可以確定 id 一定存在而且是 int（不會是 None）。

提示

讓回傳模型保證某個值一定存在、而且一定是 int（不是 None），對 API 用戶端非常有幫助。他們在有這個確信下可以寫出更簡單的程式碼。

此外，透過「自動產生的客戶端」也會有更簡潔的介面，讓要使用你 API 的開發者能有更好的開發體驗。😎

HeroPublic 中的欄位與 HeroBase 相同，僅 id 宣告為 int（非 None）：

  • id
  • name
  • age
# Code above omitted 👆

class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

HeroCreate - 用於建立 Hero 的資料模型

現在我們建立 HeroCreate 模型，這是用來「驗證」用戶端送來資料的模型。

它具有與 HeroBase 相同的欄位，並且還有 secret_name。

接下來，當用戶端「建立新 hero」時，他們會送上 secret_name，它會被儲存在資料庫中，但這些祕密名稱不會在 API 中回傳給用戶端。

提示

這也就是你處理「密碼」的方式。接收它們，但不要在 API 中回傳。

你也應該在儲存前先對密碼做「雜湊」，「永遠不要以明文儲存」。

HeroCreate 的欄位有：

  • name
  • age
  • secret_name
# Code above omitted 👆

class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

HeroUpdate - 用於更新 Hero 的資料模型

在前一版的應用中，我們沒有「更新 hero」的方式，但現在有了「多個模型」，我們就能做到。🎉

HeroUpdate 這個資料模型有點特別，它包含「建立新 hero 所需的所有欄位」，但所有欄位都是「可選的」（都有預設值）。這樣在更新時，你只需要送出想要更新的欄位即可。

因為所有欄位的「型別其實都改變了」（型別現在包含 None，而且預設值為 None），我們需要「重新宣告」它們。

其實不一定要繼承 HeroBase，因為我們會重新宣告所有欄位。我這裡保留繼承只是為了一致性，並非必要。這主要是個人偏好的問題。🤷

HeroUpdate 的欄位有：

  • name
  • age
  • secret_name
# Code above omitted 👆

class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

用 HeroCreate 建立並回傳 HeroPublic

現在我們有了「多個模型」，可以更新應用中使用它們的部分。

我們在請求中接收 HeroCreate（資料模型），並由它建立一個 Hero（資料表模型）。

這個新的資料表模型 Hero 會有用戶端傳來的欄位，並且會由資料庫產生一個 id。

然後我們直接從函式回傳這個資料表模型 Hero。但因為我們用 HeroPublic 當作 response_model，FastAPI 會用 HeroPublic 來驗證與序列化資料。

# Code above omitted 👆

@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

提示

現在我們用 response_model=HeroPublic，而不是用回傳型別標註 -> HeroPublic，因為我們實際回傳的值其實「不是」HeroPublic。

如果我們宣告 -> HeroPublic，你的編輯器與 linter 會（理所當然地）抱怨你回傳的是 Hero 而不是 HeroPublic。

在 response_model 中宣告，就是要讓 FastAPI 去做它該做的事，而不影響型別標註，以及你的編輯器與其他工具提供的協助。

使用 HeroPublic 讀取多個 Hero

我們可以像先前一樣「讀取」多個 Hero。同樣地，我們使用 response_model=list[HeroPublic] 來確保資料被正確驗證與序列化。

# Code above omitted 👆

@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

使用 HeroPublic 讀取單一 Hero

我們可以「讀取」單一 hero：

# Code above omitted 👆

@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

使用 HeroUpdate 更新 Hero

我們可以「更新 hero」。為此我們使用 HTTP 的 PATCH 操作。

在程式碼中，我們會取得一個只包含用戶端有傳送的資料的 dict，不包含只是因為有預設值而存在的欄位。為了達成這點，我們使用 exclude_unset=True。這是關鍵。🪄

然後我們使用 hero_db.sqlmodel_update(hero_data) 以 hero_data 的資料更新 hero_db。

# Code above omitted 👆

@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db

# Code below omitted 👇
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

再次刪除 Hero

「刪除」 hero 基本上維持不變。

我們不會為了重構而重構一切。😅

# Code above omitted 👆

@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
👀 Full file preview 
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


SessionDep = Annotated[Session, Depends(get_session)]
app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,
    limit: Annotated[int, Query(le=100)] = 100,
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(hero_id: int, hero: HeroUpdate, session: SessionDep):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}
🤓 Other versions and variants

Tip

Prefer to use the Annotated version if possible.

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: int | None = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: int | None = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str


class HeroUpdate(HeroBase):
    name: str | None = None
    age: int | None = None
    secret_name: str | None = None


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


def get_session():
    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):
    heroes = session.exec(select(Hero).offset(offset).limit(limit)).all()
    return heroes


@app.get("/heroes/{hero_id}", response_model=HeroPublic)
def read_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.patch("/heroes/{hero_id}", response_model=HeroPublic)
def update_hero(
    hero_id: int, hero: HeroUpdate, session: Session = Depends(get_session)
):
    hero_db = session.get(Hero, hero_id)
    if not hero_db:
        raise HTTPException(status_code=404, detail="Hero not found")
    hero_data = hero.model_dump(exclude_unset=True)
    hero_db.sqlmodel_update(hero_data)
    session.add(hero_db)
    session.commit()
    session.refresh(hero_db)
    return hero_db


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: Session = Depends(get_session)):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()
    return {"ok": True}

再次執行應用

你可以再次執行應用：

$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

如果你前往 /docs 的 API UI，你會看到它已更新，建立 hero 時不再期待從用戶端接收 id，等等。

總結

你可以使用 SQLModel 與 SQL 資料庫互動，並用「資料模型」與「資料表模型」讓程式碼更簡潔。

你可以在 SQLModel 文件學到更多內容，這裡還有一份更長的 使用 SQLModel 與 FastAPI 的教學。🚀