Does that generate a join or a not in? This is very relevant for performance.
Cheers,
Paulo Köch
On Tue, Mar 24, 2009 at 20:13, Alex Gaynor <alex.gay...@gmail.com> wrote:
>
>
> On Tue, Mar 24, 2009 at 4:05 PM, Konstantin S <ktechli...@gmail.com> wrote:
>>
>> Hello!
>>
>> I have two unrelated models that have one common field.
>>
>> class Media(models.Model):
>> title = models.CharField(max_length=500)
>> ...
>>
>> class Link(models.Model):
>> title = models.CharField(max_length=500)
>> ...
>>
>> Now I want to select those objects from the Media model that do not
>> exist in the Link model if we compare them only by 'title' field. In
>> raw SQL it looks like this:
>>
>> select * from Media left join Link on Media.title=Link.title where
>> Link.title is null;
>>
>> Is it possible to make the same thing by Django ORM only ?
>>
>>
>
> So to be clear you want all items from Media for which there isn't a link
> with that title, in the ORM that would look like:
>
> Media.objects.exclude(title__in=Link.objects.values('title'))
>
> 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
>
> >
>
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