用fastapi 和sqlite创建一个档案库管理系统

好的，下面是一个简单的示例，演示如何使用 FastAPI 和 SQLite 创建一个档案库管理系统。

首先，安装必要的库：

pip install fastapi
pip install uvicorn
pip install databases
pip install sqlalchemy

然后，创建一个 `main.py` 文件，并输入以下代码：

from fastapi import FastAPI
from pydantic import BaseModel
from typing import List
import databases
from databases import Database
import sqlalchemy
from sqlalchemy import create_engine, MetaData, Table, Column, Integer, String

app = FastAPI()

# 数据库配置信息
DATABASE_URL = "sqlite:///./test.db"

# 创建数据库连接
database = Database(DATABASE_URL)

# SQLAlchemy 元数据
metadata = MetaData()

# 模型对应的数据库表
books = Table(
    "books",
    metadata,
    Column("id", Integer, primary_key=True),
    Column("title", String(50)),
    Column("author", String(50)),
    Column("description", String(200)),
    Column("price", Integer),
)

# 创建数据库表
engine = create_engine(DATABASE_URL)
metadata.create_all(engine)


# 数据模型
class Book(BaseModel):
    title: str
    author: str
    description: str
    price: int


# 创建新书籍
@app.post("/books/")
async def create_book(book: Book):
    query = books.insert().values(
        title=book.title,
        author=book.author,
        description=book.description,
        price=book.price,
    )
    last_record_id = await database.execute(query)
    return {**book.dict(), "id": last_record_id}


# 获取所有书籍
@app.get("/books/")
async def read_books():
    query = books.select()
    results = await database.fetch_all(query)
    return results


# 获取单个书籍
@app.get("/books/{book_id}")
async def read_book(book_id: int):
    query = books.select().where(books.c.id == book_id)
    result = await database.fetch_one(query)
    if result:
        return result
    else:
        return {"error": "Book not found"}


# 更新书籍
@app.put("/books/{book_id}")
async def update_book(book_id: int, book: Book):
    query = (
        books.update()
        .where(books.c.id == book_id)
        .values(
            title=book.title,
            author=book.author,
            description=book.description,
            price=book.price,
        )
    )
    await database.execute(query)
    return {**book.dict(), "id": book_id}


# 删除书籍
@app.delete("/books/{book_id}")
async def delete_book(book_id: int):
    query = books.delete().where(books.c.id == book_id)
    await database.execute(query)
    return {"message": "Book deleted successfully"}


# 连接到数据库
@app.on_event("startup")
async def startup():
    await database.connect()


# 断开数据库连接
@app.on_event("shutdown")
async def shutdown():
    await database.disconnect()

这个示例创建了一个名为 `books` 的数据库表，用于存储书籍信息。它提供了以下 API：

- `POST /books/`：创建新书籍
- `GET /books/`：获取所有书籍
- `GET /books/{book_id}`：获取单个书籍
- `PUT /books/{book_id}`：更新书籍
- `DELETE /books/{book_id}`：删除书籍

你可以使用 SQLite 数据库浏览器等工具来管理数据。

最后，在命令行中运行以下命令启动应用程序：

uvicorn main:app --reload

现在，你可以通过浏览器或其他 HTTP 客户端来访问这些 API。例如，要创建一个新书籍：

POST http://localhost:8000/books/
{
  "title": "Python入门教程",
  "author": "张三",
  "description": "一本Python入门教程",
  "price": 50
}

要获取所有书籍：

GET http://localhost:8000/books/

要获取单个书籍：

GET http://localhost:8000/books/1

要更新书籍：

PUT http://localhost:8000/books/1
{
  "title": "Python入门教程2",
  "author": "张三",
  "description": "一本Python入门教程",
  "price": 60
}

要删除书籍：

DELETE http://localhost:8000/books/1