On Apr 16, 6:41 pm, Alex Gaynor <alex.gay...@gmail.com> wrote:
> On Thu, Apr 16, 2009 at 6:39 AM, koranthala <koranth...@gmail.com> wrote:
>
> > Hi,
> > I was comparing between signal and save() and came across this
> > following mail chain -
>
> >http://groups.google.com/group/django-users/browse_thread/thread/d0ff...
>
> > In this it is mentioned that -
> > ---
> > If you want to implement some
> > functionality that operates across multiple types of models, you need
> > to
> > use the signal infrastructure, since the same signal is raised no
> > matter
> > what the type of model (you can differentiate the model type in the
> > signal handler, though).
> > ----
>
> > I was unable to understand why we should go for signals in case we
> > have to work across models?
> > Say, for example - I have ModelA and ModelB. Everytime, I save an
> > element in ModelA, I need to update 15 fields in ModelB.
> > In this case, shouldn't I do everything in ModelA.save itself?
> > ModelA.save():
> > super.save()
> > Update 15 fields in ModelB
>
> > I do not understand why we should go for signals in this case too?
> > Sorry if I am dense :-)
>
> One of the simplest reasons to use signals in that situation is because you
> can't change the code in that application. Say you want to trigger
> something on the User object being saved, you don't want to monkey patch
> django.contrib.auth so use just use the signal for code clarity.
>
> Alex
>
> --
> "I disapprove of what you say, but I will defend to the death your right to
> say it." --Voltaire
> "The people's good is the highest law."--Cicero
Thank you Alex.
But considering the scenario mentioned above - wherein I need to make
modifications to a separate table - both of which I have full access
to - should I go ahead with signals or should I go with save?
Malcolms mail - the link mentioned earlier - seems to suggest that I
should be using signals - but I am unable to understand the
justification for it.
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