sqlachemy

https://www.sqlalchemy.org/

面向数据库的ORM工具，其仅仅做ORM工作，不做校验工作。

SQLAlchemy is the Python SQL toolkit and Object Relational Mapper that gives application developers the full power and flexibility of SQL.

It provides a full suite of well known enterprise-level persistence patterns, designed for efficient and high-performing database access, adapted into a simple and Pythonic domain language.

pydantic

https://pydantic-docs.helpmanual.io/

此工具面向输入的数据，对其进行校验，但并不对接数据库。

Documentation for version: v1.9.1

Data validation and settings management using python type annotations.

pydantic enforces type hints at runtime, and provides user friendly errors when data is invalid.

Define how data should be in pure, canonical python; validate it with pydantic.

问题引入

对于一个标准的项目，需要处理这两类问题，需要这两个工具同时使用，

由此会定义两个 数据类型

例如：

https://github.com/fanqingsong/DogeAPI

https://github.com/fanqingsong/DogeAPI/blob/main/models/models.py

#!/usr/bin/python3

from sqlalchemy import Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship

from database.configuration import Base


class Blog(Base):
    """
    Blog class
    Args:
        Base (sqlalchemy.ext.declarative.api.Base): Base class
    """

    __tablename__ = "blogs"
    id = Column(Integer, primary_key=True, index=True)
    title = Column(String)
    body = Column(String)
    user_id = Column(Integer, ForeignKey("users.id"))
    creator = relationship("User", back_populates="blogs")


class User(Base):
    """
    User class
    Args:
        Base (sqlalchemy.ext.declarative.api.Base): Base class
    """

    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String)
    email = Column(String)
    password = Column(String)
    blogs = relationship("Blog", back_populates="creator")

同时

https://github.com/fanqingsong/DogeAPI/blob/main/schema/schemas.py

#!/usr/bin/python3

from typing import List, Optional

from pydantic import BaseModel


class BlogBase(BaseModel):
    title: str
    body: str


class Blog(BlogBase):
    class Config:
        orm_mode = True


class User(BaseModel):
    name: str
    email: str
    password: str


class ShowUser(BaseModel):
    name: str
    email: str
    blogs: List[Blog] = []

    class Config:
        orm_mode = True


class ShowBlog(BaseModel):
    title: str
    body: str
    creator: ShowUser

    class Config:
        orm_mode = True


class Login(BaseModel):
    username: str
    password: str


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: Optional[str] = None

sqlmodel -- 问题解决办法

https://sqlmodel.tiangolo.com/#sqlalchemy-and-pydantic

fastapi的作者注意到了这个问题，于是发明了此ORM工具。

SQLModel is a library for interacting with SQL databases from Python code, with Python objects. It is designed to be intuitive, easy to use, highly compatible, and robust.

SQLModel is based on Python type annotations, and powered by Pydantic and SQLAlchemy.

The key features are:

• Intuitive to write: Great editor support. Completion everywhere. Less time debugging. Designed to be easy to use and learn. Less time reading docs.
• Easy to use: It has sensible defaults and does a lot of work underneath to simplify the code you write.
• Compatible: It is designed to be compatible with FastAPI, Pydantic, and SQLAlchemy.
• Extensible: You have all the power of SQLAlchemy and Pydantic underneath.
• Short: Minimize code duplication. A single type annotation does a lot of work. No need to duplicate models in SQLAlchemy and Pydantic.

数据类型定义一次， 即可做ORM，也可做pydantic模式

https://sqlmodel.tiangolo.com/tutorial/fastapi/response-model/

from typing import List, Optional

from fastapi import FastAPI
from sqlmodel import Field, Session, SQLModel, create_engine, select


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


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

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


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


app = FastAPI()


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


@app.post("/heroes/", response_model=Hero)
def create_hero(hero: Hero):
    with Session(engine) as session:
        session.add(hero)
        session.commit()
        session.refresh(hero)
        return hero


@app.get("/heroes/", response_model=List[Hero])
def read_heroes():
    with Session(engine) as session:
        heroes = session.exec(select(Hero)).all()
        return heroes

实例

https://github.com/fanqingsong/fastapi-alembic-sqlmodel-async