/Python/Django pre_save get old instance

Django pre_save get old instance

@receiver(pre_save, sender=A)
def signal_product_manage_latest_version_id(sender, instance, update_fields=None, **kwargs):
    try:
        old_instance = A.objects.get(id=instance.id)
    except A.DoesNotExist:  # to handle initial object creation
        return None  # just exiting from signal
    # your code to with 'old_instance'

Source: stackoverflow.com

Similar codes

0 vote292 views1 answer
Mongoengine ObjectIdField
Python
0 vote268 views1 answer
Python input byte array
Python
1 vote271 views1 answer
Update set python
Python
5 votes296 views2 answers
Stitch two dictionary python
Python
3 votes310 views2 answers
Jupyter print full dataframe
Python
0 vote296 views1 answer
Lowering the time.countdown python
Python
0 vote266 views1 answer
Pycaw , Python Audio Control Lib
Python
46 votes278 views6 answers
Round to decimal places python
Python
2 votes300 views2 answers
Python format 001
Python
0 vote306 views1 answer
Python if dataframe has at least one row
Python