Example
By utilizing the pre_save we can determine if a save action on our database was about updating an existing object or creating a new one.
In order to achieve this you can check the state of the model object:
@receiver(pre_save, sender=User)
def pre_save_user(sender, instance, **kwargs):
if not instance._state.adding:
print ('this is an update')
else:
print ('this is an insert')
Now every time a save action takes place, the pre_save signal will run and will print:
this is an updateif the action derived from an update action.this is an insertif the action derived from an insert action.
Note that this method does not require any additional database queries.
