Method construct

tortoise/models.py:942–1061

Create a model instance without validation, DB checks, or FK restrictions. This creates a "detached" instance that has the right shape for reading attributes and iterating relations, but is not part of the ORM lifecycle. Useful for unit testing and serialization wit

(cls: type[MODEL], _saved_in_db: bool = False, **kwargs: Any)

    @classmethod
    def construct(cls: type[MODEL], _saved_in_db: bool = False, **kwargs: Any) -> MODEL:
        """
        Create a model instance without validation, DB checks, or FK restrictions.

        This creates a "detached" instance that has the right shape for reading
        attributes and iterating relations, but is not part of the ORM lifecycle.
        Useful for unit testing and serialization without a database connection.

        Unlike ``__init__``, this method:
        - Does NOT validate field values (nullability, type checks)
        - Does NOT require FK objects to be saved to the database
        - Does NOT prevent setting backward FK, backward O2O, or M2M fields
        - Does NOT call ``to_python_value`` on data fields
        - Skips async defaults (sets them to ``None``)

        Backward FK and M2M fields are wrapped in ``ReverseRelation`` and
        ``ManyToManyRelation`` respectively with ``_fetched=True`` so that
        iteration, ``len()``, ``in``, and ``bool()`` work without raising
        ``NoValuesFetched``.

        Example::

            tournament = Tournament.construct(id=1, name="Test")
            event = Event.construct(
                name="Game",
                tournament=tournament,
                participants=[
                    Team.construct(id=1, name="Team A"),
                    Team.construct(id=2, name="Team B"),
                ],
            )
            assert event.tournament.name == "Test"
            assert event.tournament_id == 1
            assert len(event.participants) == 2

        :param _saved_in_db: Whether to mark the instance as saved in DB.
            Defaults to ``False``.
        :param kwargs: Field values to set on the instance.
        :return: A new model instance with the given field values.
        """
        self = cls.__new__(cls)
        meta = self._meta
        _setattr = object.__setattr__

        _setattr(self, "_partial", False)
        _setattr(self, "_saved_in_db", _saved_in_db)
        _setattr(self, "_custom_generated_pk", False)
        _setattr(self, "_await_when_save", {})

        # Track source fields that are auto-populated from FK/O2O objects
        # so that the default-setting loop doesn't overwrite them with None.
        populated_source_fields: set[str] = set()

        for key, value in kwargs.items():
            if key in meta.backward_fk_fields:
                # Backward FK: wrap in ReverseRelation with _fetched=True
                backward_fk: BackwardFKRelation = meta.fields_map[key]  # type: ignore
                rel = ReverseRelation(