Question

i currently have this models how do i delete the logo without deleting the company model.Please sample codes if possible thanks.

class Picture(models.Model):
    owner = models.ForeignKey(User,blank = True)
    caption = models.CharField(max_length=150, blank=True, null=True)
    image = ImageField(upload_to='images/',blank = True, null = True)

class Company(GenericUser):
    company_name = models.CharField(max_length=150,blank = True,null = True)
    logo = models.ForeignKey(Picture,blank = True,null = True)

this is a model how will i then remove the foto from the land model the model looks like this.

class Land(Properies):
    photo = models.ManyToManyField(Picture,blank=True,related_name='Land_Pictures',null = True)

i tried this bit it dose not work

checked_list = []
start = 1            
land_photos = sorted(list(land.photo.select_related()),reverse =True)
while start < 8:
    photo = 'photo%s' % start
    checked = form.cleaned_data[photo]
    if checked != None:
        checked_list.append(land_photos[start - 1])
        start += 1            
for a_foto in checked_list:
land.photo.remove(a_foto)
try:
    a_foto.remove_all_file()
    a_foto.delete()
except OSError:
    pass

i keep getting an error like that id is set to none and if i hit refresh it works i think

Exception Type:     AssertionError
Exception Value:    
Picture object can't be deleted because its id attribute is set to None.

Answer 1

Change your Company model this way:

class Company(GenericUser):
    company_name = models.CharField(max_length=150,blank = True,null = True)
    logo = models.ForeignKey(Picture,blank = True,null = True, on_delete=models.SET_NULL)

docs: https://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.ForeignKey.on_delete