Module « sqlalchemy.orm »

Fonction clear_mappers - module sqlalchemy.orm

Signature de la fonction clear_mappers

def clear_mappers() 

Description

clear_mappers.__doc__

Remove all mappers from all classes.

    .. versionchanged:: 1.4  This function now locates all
       :class:`_orm.registry` objects and calls upon the
       :meth:`_orm.registry.dispose` method of each.

    This function removes all instrumentation from classes and disposes
    of their associated mappers.  Once called, the classes are unmapped
    and can be later re-mapped with new mappers.

    :func:`.clear_mappers` is *not* for normal use, as there is literally no
    valid usage for it outside of very specific testing scenarios. Normally,
    mappers are permanent structural components of user-defined classes, and
    are never discarded independently of their class.  If a mapped class
    itself is garbage collected, its mapper is automatically disposed of as
    well. As such, :func:`.clear_mappers` is only for usage in test suites
    that re-use the same classes with different mappings, which is itself an
    extremely rare use case - the only such use case is in fact SQLAlchemy's
    own test suite, and possibly the test suites of other ORM extension
    libraries which intend to test various combinations of mapper construction
    upon a fixed set of classes.