外观
操作MySQL数据库
FastAPI不需要安装SQL数据库，但是可以操作任何关系型数据库。下面通过一个简单的示例介绍一下如何使用FastAPI结合SQLAlchemy操作MySQL数据库。
为提高代码的可读性，规定项目结构如下：
执行如下步骤实现该功能。
- 安装SQLAlchemy，命令如下：
pip install sqlalchemy- 创建MySQL数据库，命名为fastapi，命令如下：
CREATE DATABASE fastapi DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;- 使用SQLAlchemy连接数据库，在database.py中编写代码如下：
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
# SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"
SQLALCHEMY_DATABASE_URL = "mysql+pymysql://root:andy123456@localhost/fastapi?charset=utf8"
engine = create_engine(SQLALCHEMY_DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()- 创建数据模型。在models.py中编写如下代码：
from sqlalchemy import Boolean, Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from .database import Base
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True, index=True)
email = Column(String(255), unique=True, index=True)
hashed_password = Column(String(255))
is_active = Column(Boolean, default=True)
items = relationship("Item", back_populates="owner")
class Item(Base):
__tablename__ = "items"
id = Column(Integer, primary_key=True, index=True)
title = Column(String(255), index=True)
description = Column(String(255), index=True)
owner_id = Column(Integer, ForeignKey("users.id"))
owner = relationship("User", back_populates="items")- 创建pydantic模型，在schemas.py中编写如下代码：
from typing import List
from pydantic import BaseModel
class ItemBase(BaseModel):
title: str
description: str = None
class ItemCreate(ItemBase):
pass
class Item(ItemBase):
id: int
owner_id: int
class Config:
orm_mode = True
class UserBase(BaseModel):
email: str
class UserCreate(UserBase):
password: str
class User(UserBase):
id: int
is_active: bool
items: List[Item] = []
class Config:
orm_mode = True设置orm_mode=True是为了实现表关联。
- 创建CURD工具集。在curd.py中编写如下代码：
from sqlalchemy.orm import Session
from . import models, schemas
def get_user(db: Session, user_id: int):
return db.query(models.User).filter(models.User.id == user_id).first()
def get_user_by_email(db: Session, email: str):
return db.query(models.User).filter(models.User.email == email).first()
def get_users(db: Session, skip: int = 0, limit: int = 100):
return db.query(models.User).offset(skip).limit(limit).all()
def create_user(db: Session, user: schemas.UserCreate):
fake_hashed_password = user.password + "notreallyhashed"
db_user = models.User(email=user.email, hashed_password=fake_hashed_password)
db.add(db_user)
db.commit()
db.refresh(db_user)
return db_user
def get_items(db: Session, skip: int = 0, limit: int = 100):
return db.query(models.Item).offset(skip).limit(limit).all()
def create_user_item(db: Session, item: schemas.ItemCreate, user_id: int):
db_item = models.Item(**item.dict(), owner_id=user_id)
db.add(db_item)
db.commit()
db.refresh(db_item)
return db_item- 创建FastAPI应用。在main.py中编写如下代码：
from typing import List
from fastapi import Depends, FastAPI, HTTPException
from sqlalchemy.orm import Session
from . import crud, models, schemas
from .database import SessionLocal, engine
models.Base.metadata.create_all(bind=engine)
app = FastAPI()
# Dependency
def get_db():
try:
db = SessionLocal()
yield db
finally:
db.close()
@app.post("/users/", response_model=schemas.User)
def create_user(user: schemas.UserCreate, db: Session = Depends(get_db)):
db_user = crud.get_user_by_email(db, email=user.email)
if db_user:
raise HTTPException(status_code=400, detail="Email already registered")
return crud.create_user(db=db, user=user)
@app.get("/users/", response_model=List[schemas.User])
def read_users(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
users = crud.get_users(db, skip=skip, limit=limit)
return users
@app.get("/users/{user_id}", response_model=schemas.User)
def read_user(user_id: int, db: Session = Depends(get_db)):
db_user = crud.get_user(db, user_id=user_id)
if db_user is None:
raise HTTPException(status_code=404, detail="User not found")
return db_user
@app.post("/users/{user_id}/items/", response_model=schemas.Item)
def create_item_for_user(
user_id: int, item: schemas.ItemCreate, db: Session = Depends(get_db)
):
return crud.create_user_item(db=db, item=item, user_id=user_id)
@app.get("/items/", response_model=List[schemas.Item])
def read_items(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
items = crud.get_items(db, skip=skip, limit=limit)
return items在sql.app同级目录下，执行如下命令：
uvicorn sql_app.main:app --reload