Class ForeignKeyFieldInstance

tortoise/fields/relational.py:315–339

class ForeignKeyFieldInstance(RelationalField[MODEL]):
    def __init__(
        self,
        model_name: type[Model] | str,
        related_name: str | None | Literal[False] = None,
        on_delete: OnDelete = CASCADE,
        **kwargs: Any,
    ) -> None:
        super().__init__(None, **kwargs)  # type:ignore[arg-type]
        self.validate_model_name(model_name)
        self.model_name = model_name
        self.related_name = related_name
        if on_delete not in set(OnDelete):
            raise ConfigurationError(
                "on_delete can only be CASCADE, RESTRICT, SET_NULL, SET_DEFAULT or NO_ACTION"
            )
        if on_delete == SET_NULL and not bool(kwargs.get("null")):
            raise ConfigurationError("If on_delete is SET_NULL, then field must have null=True set")
        self.on_delete = on_delete

    def describe(self, serializable: bool) -> dict:
        desc = super().describe(serializable)
        desc["raw_field"] = self.source_field
        desc["on_delete"] = str(self.on_delete)
        return desc


class BackwardFKRelation(RelationalField[MODEL]):