onupdate functionality not available?

[Julian-J-S]

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Example Code

from sqlalchemy import func, DateTime

# Working with FastAPI / sqlalchemy

created_at = mapped_column(DateTime, server_default=func.now())
updated_at = mapped_column(DateTime, onupdate=func.now())

created_at = Column(DateTime, server_default=func.now())
updated_at = Column(DateTime, onupdate=func.now())


# SQLModel

created_at: datetime | None = Field(default=func.now())
updated_at = ??????????????

Description

I would like my models / tables to have a created_at and updated_at field that automatically get set on creation or update.

When working with FastAPI / sqlalchemy I have multple options to specify that using

• server_default: which creates the timestamp on the db
• onupdate: set value on each update on the db

As far as I have seen in the docs there is only a

• default: probably also called by the db itself

but there is no onupdate or similar?

I tried to integrete the sqlalchemy fields into SQLModel but this did not work.
Any way to achieve this or is this something thats in development?
thanks!

Operating System

Windows

Operating System Details

No response

SQLModel Version

0.0.19

Python Version

3.10

Additional Context

No response

[redb0]

You can use sa_column_kwargs. My example of using as an mixin class

class UpdatedAt(SQLModel):
    updated_at: Optional[datetime] = Field(
        default=None,
        sa_type=sa.DateTime(timezone=True),
        sa_column_kwargs={
            'onupdate': sa.func.now(),
            'server_default': sa.func.now(),
        },
    )

[Blackwidow-sudo]

Would be nice to have native support in Field() tho.
I did it with:

created_at: datetime = Field(sa_column=Column(DateTime, default=func.now()))
updated_at: datetime = Field(sa_column=Column(DateTime, default=func.now(), onupdate=func.now()))

[KunxiSun]

I set the updater id and update time in the add function👇🏻

from datetime import datetime

from sqlmodel import Session as _Session

class Session(_Session):

    def add(self, instance: BaseTable, *args, **kwargs) -> None:

        user_id = self.info['user_id']

        if isinstance(instance, CreatorUpdaterMixin) and user_id:
     
            if not instance.creator:
                instance.created_by = user_id
                instance.create_at = datetime.now()
            else:
                instance.updated_by = user_id
                instance.update_at = datetime.now()