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Module « sqlalchemy.orm »

Fonction defaultload - module sqlalchemy.orm

Signature de la fonction defaultload

def defaultload(*keys: '_AttrType') -> '_AbstractLoad' 

Description

help(sqlalchemy.orm.defaultload)

Indicate an attribute should load using its predefined loader style.

The behavior of this loading option is to not change the current
loading style of the attribute, meaning that the previously configured
one is used or, if no previous style was selected, the default
loading will be used.

This method is used to link to other loader options further into
a chain of attributes without altering the loader style of the links
along the chain.  For example, to set joined eager loading for an
element of an element::

    session.query(MyClass).options(
        defaultload(MyClass.someattribute).joinedload(
            MyOtherClass.someotherattribute
        )
    )

:func:`.defaultload` is also useful for setting column-level options on
a related class, namely that of :func:`.defer` and :func:`.undefer`::

    session.scalars(
        select(MyClass).options(
            defaultload(MyClass.someattribute)
            .defer("some_column")
            .undefer("some_other_column")
        )
    )

.. seealso::

    :ref:`orm_queryguide_relationship_sub_options`

    :meth:`_orm.Load.options`

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