Tortoise ORM

Tortoise ORM uses custom metaclasses and tightly controls its initialization. Do not decorate Tortoise models directly with @monk. Use the DTO (Data Transfer Object) pattern instead — it gives you a clean boundary between API validation and database persistence.

Project: https://github.com/tortoise/tortoise-orm

The integration

import dataclasses
from typing import Annotated
from tortoise.models import Model
from tortoise import fields
from monk import monk, validate
from monk.constraints import Email, Len
from monk.exceptions import ValidationError

# 1. The Database Model (Pure Persistence)
class UserDB(Model):
    id = fields.IntField(pk=True)
    username = fields.CharField(max_length=50, unique=True)
    email = fields.CharField(max_length=255, unique=True)

    class Meta:
        table = "users"

# 2. The DTO (Pure Validation)
@monk
class CreateUserDTO:
    username: Annotated[str, Len(min_len=3, max_len=50)]
    email: Annotated[str, Email]

# 3. The API / Service Handler
async def register_user(payload: dict) -> UserDB:
    try:
        # Validate at the boundary before touching the ORM
        safe_dto = validate(CreateUserDTO(**payload))
    except ValidationError as e:
        print("Request rejected:", e.flatten())
        raise

    # Unpack the proven DTO directly into Tortoise
    return await UserDB.create(**dataclasses.asdict(safe_dto))