Re: many-to-many between apps

On 31/07/2013 5:08pm, Mike Dewhirst wrote:
> Is it possible to establish a many-to-many relationship between a model
> in one app and a model in another app?

Yes. I needed to avoid importing the class and use ...

class Region(models.Model):
... various fields ...
ref = models.ManyToManyField('item.Reference')

Lovely!

Thanks for Django

>
> I've just tried to do it and run into what I think is circular import
> trouble. This is a retro-fit after initial deployment.
>
> #in item.models.reference
> class Reference(models.Model):
> ... various fields ...
> class Meta:
> app_label = 'item'
>
> #in item.models.reference_region
> from company import Region
>
> class Reference_Region(models.Model):
> region = models.ForeignKey(Region)
> reference = models.ForeignKey(Reference)
> class Meta:
> app_label = 'item'
>
>
> #in company.models.region
> from item import Reference
>
> class Region(models.Model):
> ... various fields ...
> ref = models.ManyToManyField(Reference)
>
> I have tried it the other way declaring the many-to-many field in
> Reference and the same thing happens.
>
> ImportError: cannot import name Reference
> and
> ImportError: cannot import name Region
> respectively
>
> Any ideas appreciated
>
> Thanks
>
> Mike
>

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