Function make_transient

lib/sqlalchemy/orm/session.py:5346–5408

Alter the state of the given instance so that it is :term:`transient`. .. note:: :func:`.make_transient` is a special-case function for advanced use cases only. The given mapped instance is assumed to be in the :term:`persistent` or :term:`detached` state. The functi

(instance: object)

def make_transient(instance: object) -> None:
    """Alter the state of the given instance so that it is :term:`transient`.

    .. note::

        :func:`.make_transient` is a special-case function for
        advanced use cases only.

    The given mapped instance is assumed to be in the :term:`persistent` or
    :term:`detached` state.   The function will remove its association with any
    :class:`.Session` as well as its :attr:`.InstanceState.identity`. The
    effect is that the object will behave as though it were newly constructed,
    except retaining any attribute / collection values that were loaded at the
    time of the call.   The :attr:`.InstanceState.deleted` flag is also reset
    if this object had been deleted as a result of using
    :meth:`.Session.delete`.

    .. warning::

        :func:`.make_transient` does **not** "unexpire" or otherwise eagerly
        load ORM-mapped attributes that are not currently loaded at the time
        the function is called.   This includes attributes which:

        * were expired via :meth:`.Session.expire`

        * were expired as the natural effect of committing a session
          transaction, e.g. :meth:`.Session.commit`

        * are normally :term:`lazy loaded` but are not currently loaded

        * are "deferred" (see :ref:`orm_queryguide_column_deferral`) and are
          not yet loaded

        * were not present in the query which loaded this object, such as that
          which is common in joined table inheritance and other scenarios.

        After :func:`.make_transient` is called, unloaded attributes such
        as those above will normally resolve to the value ``None`` when
        accessed, or an empty collection for a collection-oriented attribute.
        As the object is transient and un-associated with any database
        identity, it will no longer retrieve these values.

    .. seealso::

        :func:`.make_transient_to_detached`

    """
    state = attributes.instance_state(instance)
    s = _state_session(state)
    if s:
        s._expunge_states([state])

    # remove expired state
    state.expired_attributes.clear()

    # remove deferred callables
    if state.callables:
        del state.callables