Django does not threat exceptions

Question

Could you please help me? Django does not threat the exceptions. I would like it returns the integrity exception block when this case occur. But nothing, it continue to the else block which raise the integrity exception. I tried with from django.db.utils import IntegrityError and from django.db import IntegrityError

        datafile = csv.DictReader(datafile, delimiter=',')
        roadnetwork = RoadNetwork.objects.get(id=pk)
                                  
        for row in datafile:
            row = {k: None if not v else v for k, v in row.items()}

            try:
                road_type_id = row['id']
                name = row['name']
                roadtype = RoadType(
                    road_type_id=road_type_id,
                    name=name,
                    congestion=CONGESTION_TYPES[row['congestion'].lower()],
                    default_speed=row.get('default_speed', None),
                    default_lanes=row.get('default_lanes', None),
                    default_param1=row.get('default_param1', None),
                    default_param2=row.get('default_param2', None),
                    default_param3=row.get('default_param3', None),
                    color=row.get('color', None))
                 
            except IntegrityError:
                e = 'this data already exists in the database'
                
                return render(request, template,  context={'e': e})

            else:
                roadtype = RoadType(
                    road_type_id=road_type_id,
                    name=name,
                    congestion=CONGESTION_TYPES[row['congestion'].lower()],
                    default_speed=row.get('default_speed', None),
                    default_lanes=row.get('default_lanes', None),
                    default_param1=row.get('default_param1', None),
                    default_param2=row.get('default_param2', None),
                    default_param3=row.get('default_param3', None),
                    color=row.get('color', None),
                    network=roadnetwork)
                 

Answer 1

You need to be committing the item to the database:

try:
    roadtype = RoadType.objects.create(
        ...
    )
except IntegrityError:
    ...
else:
    ...

Currently this will create the object, but not save it to the database, so you can't get an IntegrityError.