Quick-Start

If you use SQLModel, please go directly to the SQLModel chapter

Minimal Example

Warning

Prerequisites,Prepare our db, Only asynchronous mode is supported,aiomysql or aiosqlite

db.py

from sqlalchemy.orm import DeclarativeBase, declared_attr
from typing import AsyncGenerator
from sqlalchemy.orm import sessionmaker
from sqlalchemy.pool import NullPool
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
DATABASE_URL = "sqlite+aiosqlite:///crud.db"

class MappedBase(DeclarativeBase):
    @declared_attr.directive
    def __tablename__(cls) -> str:
        return cls.__name__.lower()


class Base(MappedBase):
    __abstract__ = True


engine = create_async_engine(
    DATABASE_URL,
    echo=False,
    poolclass=NullPool
)

SessionLocal = sessionmaker(
    autocommit=False,
    autoflush=False,
    bind=engine,
    class_=AsyncSession,
    expire_on_commit=False,
)


async def get_session() -> AsyncGenerator[AsyncSession, None]:
    async with SessionLocal() as session:
        yield session


async def init_db():
    async with engine.begin() as conn:
        await conn.run_sync(MappedBase.metadata.create_all)

First Define Your Model And Schema

model.py

from sqlalchemy import String, Integer, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column
from .db import Base


class Pet(Base):
    __tablename__ = "pet"
    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(100))
    description: Mapped[str] = mapped_column(String(100))

schema.py

from typing import Optional, List
from pydantic import BaseModel


class PetBase(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None


class PetPublic(PetBase):
    id: int


class PetCreate(PetBase):
    pass


class PetUpdate(PetBase):
    pass

Next we need to create a service:

service.py

from better_crud.service.sqlalchemy import SqlalchemyCrudService
from .model import Pet


class PetService(SqlalchemyCrudService[Pet]):
    def __init__(self):
        super().__init__(Pet)

Next we need to define the controller and decorate it with the crud decorator Sure the controller is just a normal class,The crud decorator gives it super powers

controller.py

from fastapi import APIRouter, Depends
from better_crud import crud
from .schema import PetCreate, PetUpdate, PetPublic
from .service import PetService

pet_router = APIRouter()


@crud(
    pet_router,
    dto={
        "create": PetCreate,
        "update": PetUpdate
    },
    serialize={
        "base": PetPublic,
    }
)
class PetController():
    service: PetService = Depends(PetService)

Next we can register router to the fastapi routing system

main.py

from better_crud import BetterCrudGlobalConfig
from fastapi import FastAPI
from contextlib import asynccontextmanager
from .db import get_session, init_db

BetterCrudGlobalConfig.init(
    backend_config={
        "sqlalchemy": {
            "db_session": get_session
        }
    }
)


@asynccontextmanager
async def lifespan(_: FastAPI):
    await init_db()
    # Shutdown
    yield

app = FastAPI(lifespan=lifespan)


def register_router():
    from app.controller import pet_router
    app.include_router(pet_router, prefix="/pet")


register_router()

And it's all done, just go to /docs and the crud endpoints are created.