How to avoid repetition in Django model fields? - django

Question

I have models that share many common fields. For example:
class Customer(models.Model):
name = models.CharField()
email = models.CharField()
address = models.CharField()
phone = models.CharField()
city = models.CharField()
state = models.CharField()
country = models.CharField()
wallet = models.FloatField()
class Seller(models.Model):
# same fields from Customer class, except the field wallet
To avoid repeating these fields, I have tried to create classes with these common fields and link using OneToOneField:
class ContactInformation(models.Model):
phone = models.CharField()
email = models.CharField()
class AddressInformation(models.Model):
address = models.CharField()
city = models.CharField()
state = models.CharField()
country = models.CharField()
class Customer(models.Model):
wallet = models.FloatField()
contact_information = models.OneToOneField(ContactInformation)
address_information = models.OneToOneField(AddresssInformation)
class Seller(models.Model):
contact_information = models.OneToOneField(ContactInformation)
address_information = models.OneToOneField(AddresssInformation)
But now it gets very messy if I try to create a ModelForm based on the Customer, as there is only the wallet field in it. To display my other OneToOneFields I have to create multiple forms: a form for the contact information and another for address information, as ModelForms don't simply display these OneToOneFields as a single form. The views get bloated, as I have to validate 3 forms in total and have to manually create the object instances.
Am I missing something here? Should I use inheritance instead? Should I just repeat these fields to have simpler forms and views? Any advice would be greatly appreciated.

Answer 1

Take a look at abstract base classes, it provides a clean way to reuse common fields to multiple tables.
You might consider:
from django.db import models
class CommonUserInfo(models.model)
name = models.CharField()
email = models.CharField()
address = models.CharField()
phone = models.CharField()
city = models.CharField()
state = models.CharField()
country = models.CharField()
class Meta:
abstract = True
class Customer(CommonUserInfo):
wallet = models.FloatField()
class Seller(CommonUserInfo):
pass
I am not sure what the benefit of using a foreign key for address information is unless you have multiple customers/sellers using the same address and the addresses will need to be updated in unison.