How create a ModelMixin?

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Example Code

from datetime import datetime
from typing import Optional

from sqlalchemy.orm import declared_attr
from sqlmodel import Field, Relationship, SQLModel


class ModelMixin:
    __name__: str
    __config__ = {}

    created_at: datetime = Field(default_factory=datetime.utcnow)
    update_at: datetime = Field(default=datetime.utcnow)
    deleted_at: datetime = Field(default=None, nullable=True)


class Phone(ModelMixin, SQLModel, table=True):

    id: Optional[int] = Field(default=None, primary_key=True)
    cellphone: str
    is_active: Optional[bool] = Field(default=True)

Description

• Created the ModelMixin with fields
• Created the model Phone
• extends ModelMixin in Phone
• When run code “SQLModel.metadata.create_all(self._engine)” only fields in Phone is created
• The fields created_at, update_at and deleted_at is ignorated

Operating System

macOS

Operating System Details

macos 12.3.1

SQLModel Version

0.0.6

Python Version

Python 3.9.9

Additional Context

No response

[byrman]

Indeed, a pure mixin does not appear to work, but perhaps you can do this as a workaround:

class ModelMixin(SQLModel):
    pass


class Phone(ModelMixin, table=True):
    pass

[byrman]

Didn’t you fix this in https://github.com/tiangolo/sqlmodel/pull/256/files ?

That fix works fine for methods and simple attributes, but unfortunately not for model fields, which have to be processed by metaclass machinery. I didn’t realise that until I tried this use case.