Insert duplicate column value in Django

Question

Is there any way how can I duplicate value to another column,the value should be the same whenever I upload data to column 1 for example. I have 3000 in column 1, the value of column 2 should automatically write 3000, it is possible to trick in models? or When Inserting query instead using default? Thanks in advance!.

Current output

Column 1         Column 2
 5000              5000
 3650              5000
 2000              5000

Expected output

Column 1         Column 2
 5000              5000
 3650              3650
 2000              2000

models.py

class Person(models.Model):
    amount = models.CharField(max_length=50,blank=True, null=True)
    amount_paid = models.CharField(max_length=60,default='5000', null=True)

@Klaus D. Yes, second column should be the same in first column,eg amount _paid should the same value in amount — Marie Loise
– Marie Loise, Commented Jan 29, 2021 at 7:02
@MarieLoise : As mentioned in link i have shared. you can overwrite your save method which will take information from first column and assign it to second column — Akash senta
– Akash senta, Commented Jan 29, 2021 at 7:03
But why do you need a second column? You could just use the first one. It has the same value. — Klaus D.
– Klaus D., Commented Jan 29, 2021 at 7:04

ruddra · Accepted Answer · 2021-01-29 07:14:21Z

You can simply override the save method:

class Person(models.Model):
    amount = models.CharField(max_length=50,blank=True, null=True)
    amount_paid = models.CharField(max_length=60,default='5000', null=True)

    def save(self, *args, **kwargs):
       self.amount_paid = self.amount
       super().save(*args, **kwargs)

But there is no need to store duplicate values unless you need it, you can simply add a boolean field, is_paid and set it True as default.

Also there is a certain pitfall of the given solution, that is if you change the amount, amount_paid will be changed automatically. If you want to update amount_paid if the Person instance is created, then you can add a if else logic:

def save(self, *args, **kwargs):
    if not self.pk:  # instance not created yet
       self.amount_paid = self.amount
    super().save(*args, **kwargs)

Alternativly, you can use Django Queryset to update bulk amount of amount_paid. For example:

from django.db.models import F
Person.objects.filter(pk__in=[1,2,3]).update(amount_paid=F('amount'))

Collectives™ on Stack Overflow

Insert duplicate column value in Django

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related