Re: queryset minimization

The biggest hit is probably going to be the reg.group call. You can
optimize that by using select_related (), which will take what is
currently 1 + (number of group registrations for the user) queries and
turn it into 2 queries:

reg = p.groupregistration_set.all().select_related('group')

More on select_related:
https://docs.djangoproject.com/en/dev/ref/models/querysets/#select-related

_Nik

On 3/6/2013 11:18 PM, Fatih Tiryakioglu wrote:
> Hi all,
>
> Is there any shortcut (minimum db hit) for the following querysets:
>
> p = Person.objects.get(mail="person1@ex.com")
> p.password & form.password comparison and it is ok.
>
> #reversing to the person's groupregisteration, for example:
> reg = p.groupregistration_set.all() #groupregistratin model is simply
> person (foreign key) and group (foreign key)
>
> #evaluating group of reg list.
> g = reg.group (for the every member of reg list)
>
> #and finally group name
> n = g.name (for the every member of g list)
>
> Which queryset or querysets hits the db, and how can I minimize it.
>
>
>
> Thanks.
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