How to put a constraint using foreign key fields in Django?

Asked Apr 29 '22 at 03:58

Active Apr 29 '22 at 04:09

Viewed 333 times

Consider following models:

class Model1:
    x = an integer
    y = an integer

class Model2:
    f1 = models.ForeignKey(Model1)
    f2 = models.ForeignKey(Model1)

Now, I want to put a constraint on model 2 such that no duplicate pairs of f1.x and f2.x get inserted in model 2.

How should I achieve it? I will be populating model 2 using bulk_create so maybe customising clean() or save() won't work.

I'm new to Django and not able to figure it out. Any help will be appreciated.

But it's not helpful in my case.

edited Apr 29 '22 at 04:07

asked Apr 29 '22 at 03:58

Divyalok Jaiswal

@solarissmoke how can I access the x field of Model1 from model2 in unique constraint? – Divyalok Jaiswal Apr 29 '22 at 04:10
Why do you think the other answer won't work for you? – Art Apr 29 '22 at 04:19
@Art because I need to access the field from foreign key i.e. I need to access x from f1 and from f2 for setting the constraint. How can I do that? – Divyalok Jaiswal Apr 29 '22 at 04:23
Eg: `Model2.objetcs.filter(f1__x=1)` or `Model2.objects.filter(f1=1)` this will return all the x that is 1 from model2 – Art Apr 29 '22 at 04:36
I understand that but I need to add a constraint on database level and not application level. – Divyalok Jaiswal Apr 29 '22 at 04:58

0 Answers0