On Aug 21, 2008, at 9:19 AM, GustaV wrote:
> > Hi all! > I'm looking for an easy way to get informed when someone append or > remove an object from a specific one-to-many relation. For example to > keep a count on the parent object, with no need to query the children. > There are a lot of stuff about it, but I'm not sure how to do it > really: > > - 1st : > http://markmail.org/message/oyt57qx3247jdhgi#query:sqlalchemy > %20__sa_instrument_class__+page:1+mid:wz4wkumhvnnm74yw+state:results > Does not seem to work on 0.5 this is the correct approach. The names have changed per examples/ custom_attributes/custom_management.py . from sqlalchemy import * from sqlalchemy.orm import * from sqlalchemy.orm.interfaces import AttributeExtension class ReceiveEvents(AttributeExtension): def append(self, obj, child, initiator): print "append", obj, child def remove(self, obj, child, initiator): print "remove", obj, child def set(self, obj, child, oldchild, initiator): print "set", obj, child listener = ReceiveEvents() class SetListener(InstrumentationManager): def instrument_attribute(self, class_, key, inst): inst.impl.extensions.append(listener) if __name__ == '__main__': m = MetaData() t = Table('t', m, Column('a', Integer, primary_key=True), Column('b', String)) class C(object): __sa_instrumentation_manager__ = SetListener mapper(C, t) c1 = C() c1.a = 4 c1.b = "test" --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
