Django Create and Save Many instances of model when another object are created

Question

I am designing a game of chess and I would like to initialize the fields with chess figures (State model) after the start of a new ChessParty.
I read about

Answer 1

Using save():

If you want to use the save() method, you could do the following:

def save(self, *args, **kwargs):
    OtherModel.objects.create(something=kwargs['something'])
    YetAnotherModel.objects.create(
        something_else=kwargs['something_else']
    )
    super(ChessParty, self).save(*args, **kwargs)

As @e4c5 states in his comment, it is easier to implement and that is why I include it!

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My take on the problem:

Although you could do this on the save(), I would recommend instead to use a signal.

Specifically use a post_save signal. Here is how to do this:

1. Create a file your_app/signals.py:

   from django.db.models.signals import post_save
   from django.dispatch import receiver
   
   from your_app.models import ChessParty, OtherModel, YetAnotherModel
   
   
   @receiver(post_save, sender=ChessParty)
   def change_my_name_plz (sender, instance, created, **kwargs):
       if created:
           OtherModel.objects.create(something=kwargs['something'])
           YetAnotherModel.objects.create(
               something_else=kwargs['something_else']
           )
   

2. You now need to override the ready() function on your_app/app.py:

   from django.apps import AppConfig
   
   class YourAppConfig(AppConfig):
       name = 'your_project.your_app'
   
       def ready(self):
           import your_project.your_app.signals
   

3. Finally, add the following in your_app/__init__.py:

   default_app_config = 'your_project.your_app.apps.YourAppConfig'
   

Now you have a signal that will create an OtherModel and YetAnotherModel objects right after you create a new ChessParty object.

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Alternative way to define signals:

There is an alternative way that does not use the @receiver decorator, but the connect() method:

1. your_app/signals.py:

   from your_app.models import ChessParty, OtherModel, YetAnotherModel
   
   
   def change_my_name_plz (sender, instance, created, **kwargs):
       if created:
           OtherModel.objects.create(something=kwargs['something'])
           YetAnotherModel.objects.create(
               something_else=kwargs['something_else']
           )
   

2. your_app/app.py:

   from django.apps import AppConfig
   from django.db.models.signals import post_save
   
   from your_app.models import ChessParty
   from your_project.your_app.signals import change_my_name_plz
   
   class YourAppConfig(AppConfig):
       name = 'your_project.your_app'
   
       def ready(self):
           post_save.connect(change_my_name_plz, sender=ChessParty)
   

3. your_app/__init__.py stays the same as above (step 3).

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