CODEWITHSUNDEEP
djangodjango-modelsdjango-signals
Kermit
Kermit

Reputation: 5992

Django detect changes to multiple fields in same model

I'm using some javascript libraries that won't let me pass in self.full_name created using def full_name(self):

Wondering how I should go about updating a full_name field based on changes to (or creation of) any of the 3 name fields.

class Employee(models.Model):
  first_name = StringProperty(max_length=25)
  middle_name = StringProperty(max_length=25)
  last_name = StringProperty(max_length=50)

  full_name = StringProperty(max_length=100)
  # lots of Icelanders have the same first and last name...
  full_name_includes_middle_name = BooleanProperty(default=False)

Right now I'm looking into @receiver and created or update_fields is looking promising...

@receiver(post_save, sender=Employee)
def update_full_name(sender, update_fields, created, instance, **kwargs):
  if instance.middle_name_is_part_of_full_name == True:
    if created or update_fields is 'first_name' or 'middle_name' or 'last_name':
      instance.full_name = instance.first_name + " " + instance.middle_name + " " + instance.last_name
      instance.save()
  else:
    if created or update_fields is 'first_name' or 'last_name':
      self.full_name = self.first_name + " " + self.last_name
      instance.save()

^ but this gives the error: 

update_full_name() missing 1 required positional argument: 'update_fields'

Upvotes: 1

Views: 295

Answers (1)

Youssef BH
Youssef BH

Reputation: 582

In this case there is no diff between create or update operation.

You can try this:

@receiver(pre_save, sender=Employee)
def update_full_name(sender, instance, **kwargs):
  if instance.middle_name_is_part_of_full_name == True:
      instance.full_name = f"{instance.first_name} {instance.middle_name} {instance.last_name}"
  else:
      instance.full_name = f"{instance.first_name} {instance.last_name}"

Upvotes: 1

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