Using sa_column with onupdate in parent model leads to sqlalchemy.exc.ArgumentError:

[Igralino]

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Example Code

from datetime import datetime
from typing import Optional

from sqlalchemy import Column, DateTime, func
from sqlalchemy.orm import declared_attr
from sqlmodel import SQLModel, Field


class BaseModel(SQLModel):
    @declared_attr
    def __tablename__(cls) -> str:
        return cls.__name__.replace("Model", "").lower() + "s"

    created_at: datetime = Field(default_factory=datetime.now, nullable=False)
    updated_at: Optional[datetime] = Field(sa_column=Column(DateTime(), onupdate=func.now()))

class UserModel(BaseModel, table=True):
    id: str = Field(primary_key=True, min_length=1, max_length=200)
    name: str = Field(max_length=200, min_length=1)

Description

• I've created a BaseModel with updated_at: Optional[datetime] = Field(sa_column=Column(DateTime(), onupdate=func.now())) field (took it from How to add current date time by default on a table declaration? #594)
• Then I made an ancestor of the BaseModel - the UserModel
• Then I run alembic revision --autogenerate and it falls with error
  sqlalchemy.exc.ArgumentError: Column object 'updated_at' already assigned to Table 'users'

I saw #743, but it is not my case, because I want to use onupdate feature

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.14

Python Version

3.12.1

Additional Context

Alembic version: 1.13.0

[jp-u]

Ran into the same issue, however, it has only arisen once I've attempted to inherit an additional table model from the BaseModel (ie CarModel(BaseModel, table=True)

[snehith-kintsugi]

Did you figure out a solution for this?

[Igralino]

Nope 😢

[joachimhuet]

Hey there,

Head over there: #876 (comment) to get an answer to your question.

The problem is in using sqlalchemy Column, try using sa_column_args and sa_column_kwargs instead 😄