how do catch A 'UNIQUE constraint failed' 404 in django

Question

How do I specifically catch a UNIQUE constraint failed 404 in the following code, I know I have to add something in the ( here? ) section

try:     q = AnswerModel(user=user, yes_question=question_model)     q.save() except ( here? ):     return HttpResponseRedirect('/user/already_exists') 

Answer 1

from django.db import IntegrityError  except IntegrityError: 

This is what you need.

EDITED for @mbrochh:

from django.db import IntegrityError  except IntegrityError as e:      if 'unique constraint' in e.message: # or e.args[0] from Django 1.10         #do something 

Yes, you can be more precise but in question case UNIQUE failed is highly likely.

Answer 2

IMHO, I would recommend to resolve this situation by get_or_create().

new_obj, created = AnswerModel.objects.get_or_create(user=user, yes_question=question_model) if created:     do_something_for_new_object(new_obj) else:     logging.error("Duplicated item.")     return