from typing import TypedDict
from sqlalchemy.orm import Mapped, MappedAsDataclass, declarative_mixin, declared_attr, mapped_column
from sqlalchemy.sql.schema import _InsertSentinelColumnDefault # pyright: ignore [reportPrivateUsage]
from typing_extensions import NotRequired
[docs]
class SentinelKwargs(TypedDict):
init: NotRequired[bool]
[docs]
@declarative_mixin
class SentinelMixin:
"""Mixin to add a sentinel column for SQLAlchemy models."""
__abstract__ = True
_sentinel_kwargs: SentinelKwargs = {}
def __init_subclass__(cls) -> None:
super().__init_subclass__()
if issubclass(cls, MappedAsDataclass):
cls._sentinel_kwargs["init"] = False
@declared_attr
def _sentinel(cls) -> Mapped[int]:
return mapped_column(
name="sa_orm_sentinel",
insert_default=_InsertSentinelColumnDefault(),
_omit_from_statements=True,
insert_sentinel=True,
use_existing_column=True,
nullable=True,
**cls._sentinel_kwargs,
)
