The only other way that I could think to do it would be to write your own M2M object. Just an object with two foreign key fields to reference X and Y. In that object you could overwrite the save method to check for which relations currently exist for a given reference to X and update accordingly. I'm not sure this would work for you, but it might be an alternative, although it violates the DRY principle.
Furbee On Thu, Jan 12, 2012 at 9:20 AM, Jeff <jbla...@mitre.org> wrote: > > On Jan 11, 9:23 pm, Dennis Lee Bieber <wlfr...@ix.netcom.com> wrote: > > On Wed, 11 Jan 2012 17:26:44 +0000, Tom Evans <tevans...@googlemail.com> > > wrote: > > > > >On Wed, Jan 11, 2012 at 5:22 PM, Jeff <jbla...@mitre.org> wrote: > > >> When Device.netgroups (a M2M field) changes, we need to perform > > >> some python-ldap operations. > > > > >Have you considered simply going back to the database to check what > > >the values currently are? It would be inefficient, but clean and > > >concise. > > > > I've forgotten how many means of changing this data there are, > > but... > > Dennis, > > Several. > > A web-only solution won't work. > > I found the 'm2m_changed' signal yesterday, read that you can't > determine *what* changed by using it, and also ended up directed > to some open bug reports... etc... and threw up my hands. > > To the best of my digging, there is no way to accurately tell > in SomeModel.save() whether the previous value of MyM2MField > and the new value are the same, and/or what the differences > are. > > I ended up completely restructuring stuff (I'll spare you the > details) so that I can just say "whatever .netgroups looks > like AFTER save, make LDAP look exactly like that." This > is essentially what Tom Evans suggested in his reply. It's > inefficient, and clearly a workaround, but is at least doable. > > It boils down in LDAP-terms to saying "replace all attribute > values for X with the following full data. I don't care what > your old data was." ... instead of saying, "remove value Y > from the 1000 values set on X" :| > > Thank you all for your efforts to help. > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To post to this group, send email to django-users@googlegroups.com. > To unsubscribe from this group, send email to > django-users+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/django-users?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
