Class DatabaseDefault

tortoise/fields/base.py:44–73

Sentinel indicating that the database should apply its default value. When a field has ``db_default`` and the user does not provide a value, this object is set as the attribute value on the model instance. During INSERT compilation it is detected via ``isinstance()`` checks: - Sing

class DatabaseDefault:
    """Sentinel indicating that the database should apply its default value.

    When a field has ``db_default`` and the user does not provide a value,
    this object is set as the attribute value on the model instance.

    During INSERT compilation it is detected via ``isinstance()`` checks:
    - Single-insert path: columns with DatabaseDefault are omitted from the
      INSERT statement, so the DB applies its DEFAULT.
    - Bulk-insert path: columns where *all* instances hold DatabaseDefault
      are omitted; mixed usage raises ``OperationalError``.
    """

    def __init__(self, field: Field) -> None:
        self.field = field

    def __repr__(self) -> str:
        return f"DatabaseDefault({self.field.model_field_name!r})"

    def __str__(self) -> str:
        return "<DB_DEFAULT>"

    def __bool__(self) -> bool:
        """Returns False so that ``if instance.field:`` is falsy for unset db_default fields.

        This is consistent with "no value has been set yet". Users who need to
        distinguish between DatabaseDefault and other falsy values should use
        ``isinstance(value, DatabaseDefault)``.
        """
        return False


class OnDelete(StrEnum):