On Thursday, September 26, 2019 at 1:07:29 PM UTC-4, Simon King wrote:
> That sounds like it would have to be application-specific. I don't
> know how SQLAlchemy can tell that you've finished adding tables and
> mappers.
Some of that is application specific, but there must be an event that can
let me figure that out...
It looks like I may be able to handle it with event:
from sqlalchemy import event
from sqlalchemy.orm import mapper
@event.listens_for(mapper, 'mapper_configured')
def mapper_configured__mapper(mapper, class_):
if not hasattr(class_, '_association_proxies'):
class_._association_proxies = {}
for k, v in dict(class_mapper(class_).all_orm_descriptors).items():
if isinstance(v, AssociationProxy):
class_._association_proxies[k] = (v.target_collection, v.
value_attr)
that appears to trigger only once, when the class is mapped.
If I were to map again, I can catch that. But it's not being invoked on
every query or session...
this will likely break on more advanced association proxies... but it's
solving my immediate problem.
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