the backrefs intentionally don't keep fanning deep into object graph
for this kind of thing, so if you want it to go one hop further you
can add an event to do that directly:
from sqlalchemy import event
from sqlalchemy.orm import attributes
@event.listens_for(Address.user, "set")
def _intercept_set(target, value, oldvalue, initiator):
if isinstance(oldvalue, User) and "address" in oldvalue.__dict__:
attributes.set_committed_value(oldvalue, "address", None)
the "set_committed_value" is to avoid triggering any new events which
will cause a recursion overflow.
On Wed, Mar 28, 2018 at 10:49 AM, Serhii Mozghovyi <egnart...@gmail.com> wrote:
> Is it possible to make child objects (many-to-one side) delete itself from
> the old parent's collection when it is added to a different parent?
> See the file attached. The old parent remains unaware that he doesn't have
> this child anymore.
>
> P.S. session.expire() is an obvious solution but too heavy. I expect some
> event-based collection synchronization, much like backref (back_populates)
> connected collections.
>
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> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
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SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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Example. See http://stackoverflow.com/help/mcve for a full description.
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