GeezerVison

Please merge it asap :3. I need it, lol.

hey can we get this merged in

@tiangolo Could you please take a look at this MR. The functionality is very nice. Would be a nice addition. Doesn't seem to clash with overall design

    class Item(SQLModel, table=True):
        id: Optional[int] = Field(default=None, primary_key=True)
        value: float
        hero_id: int = Field(foreign_key="hero.id")
        hero: "Hero" = Relationship(back_populates="items")

    class Hero(SQLModel, table=True):
        id: Optional[int] = Field(default=None, primary_key=True)
        name: str
        items: List[Item] = Relationship(back_populates="hero")

        @declared_attr
        def total_items(cls):
            return column_property(cls._total_items_expression())

        @classmethod
        def _total_items_expression(cls):
            return (
                select(func.coalesce(func.sum(Item.value), 0))
                .where(Item.hero_id == cls.id)
                .correlate_except(Item)
                .label("total_items")
            )

        @declared_attr
        def status(cls):
            return column_property(
                select(
                    case(
                        (cls._total_items_expression() > 0, "active"), else_="inactive"
                    )
                ).scalar_subquery()
            )

Following this example I am getting

pydantic.errors.PydanticUserError: A non-annotated attribute was detected: `total_items = <sqlalchemy.orm.decl_api.declared_attr object at 0x10e415350>`. All model fields require a type annotation; if `total_items` is not meant to be a field, you may be able to resolve this error by annotating it as a `ClassVar` or updating `model_config['ignored_types']`.

Even if I do def total_items(cls): -> int I still get the same error.
SQLModel version 0.0.16

But I think we can get the same result with computed_field and the property decorator

    from pydantic import computed_field

    class Hero(SQLModel, table=True):
        id: Optional[int] = Field(default=None, primary_key=True)
        name: str
        items: List[Item] = Relationship(back_populates="hero")

        @computed_field
        @property
        def total_items(cls) -> int:
            return len(self.items)

Any movement to get this functionality in?

any updates on this?

This pull request has a merge conflict that needs to be resolved.

I think I can go a bit further than what this pr had in mind. I was thinking about combining computed_feilds and hybrid_property column_property and declared_attr together. Does anyone have any tips and suggestions? I'll try and use what this pr had in mind as a blueprint.

@50Bytes-dev Glad to see your pr is still alive, mind if I help you review it?

@50Bytes-dev Have you tried adding some tests to the pytest to ensure that this implementation works?

@50Bytes-dev Have you tried adding some tests to the pytest to ensure that this implementation works?

Yes, I have basic tests. I use this PR in the production of my projects and make sure that everything works correctly.

@50Bytes-dev thanks, for that piece of code. Is there any chance for release some time soon. I have a use case starting from next week and I'd like to omit a vanilla sqlalchemy workaround :)

@50Bytes-dev thanks, for that piece of code. Is there any chance for release some time soon. I have a use case starting from next week and I'd like to omit a vanilla sqlalchemy workaround :)

Release where? Personally, I just use the repository and don't plan to release anything anywhere. I recommend trying it this way too, it's quite convenient.

dependencies = [
  "sqlmodel",
]

[tool.uv.sources]
sqlmodel = { git = "https://github.com/50Bytes-dev/sqlmodel.git", rev = "833b8700e5006177d1a57fd8b3109bd625a358de" }

@50Bytes-dev Okay, sorry. I thought that the PR is meant to be merged at some point.

@50Bytes-dev Okay, sorry. I thought that the PR is meant to be merged at some point.

I think that the main repository is dead and unlikely to be developed further, so I created my own fork where I implement all the necessary functions myself.

I think that the main repository is dead

The main repo of what? FastAPI, SQLmodel?

If there is no PR, in SQLModel I assume, nobody can check it, thus it appears obv. dead. Though if you look at the commit history in main, all is fine

Looking for a method to introduce calculated column easily. Got to this to just read that lol