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Classe « Connection »

Méthode sqlalchemy.Connection.invalidate

Signature de la méthode invalidate

def invalidate(self, exception: 'Optional[BaseException]' = None) -> 'None' 

Description

help(Connection.invalidate)

Invalidate the underlying DBAPI connection associated with
this :class:`_engine.Connection`.

An attempt will be made to close the underlying DBAPI connection
immediately; however if this operation fails, the error is logged
but not raised.  The connection is then discarded whether or not
close() succeeded.

Upon the next use (where "use" typically means using the
:meth:`_engine.Connection.execute` method or similar),
this :class:`_engine.Connection` will attempt to
procure a new DBAPI connection using the services of the
:class:`_pool.Pool` as a source of connectivity (e.g.
a "reconnection").

If a transaction was in progress (e.g. the
:meth:`_engine.Connection.begin` method has been called) when
:meth:`_engine.Connection.invalidate` method is called, at the DBAPI
level all state associated with this transaction is lost, as
the DBAPI connection is closed.  The :class:`_engine.Connection`
will not allow a reconnection to proceed until the
:class:`.Transaction` object is ended, by calling the
:meth:`.Transaction.rollback` method; until that point, any attempt at
continuing to use the :class:`_engine.Connection` will raise an
:class:`~sqlalchemy.exc.InvalidRequestError`.
This is to prevent applications from accidentally
continuing an ongoing transactional operations despite the
fact that the transaction has been lost due to an
invalidation.

The :meth:`_engine.Connection.invalidate` method,
just like auto-invalidation,
will at the connection pool level invoke the
:meth:`_events.PoolEvents.invalidate` event.

:param exception: an optional ``Exception`` instance that's the
 reason for the invalidation.  is passed along to event handlers
 and logging functions.

.. seealso::

    :ref:`pool_connection_invalidation`

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