How to access reverse relationship in django models? - django

Question

I have two models one for User and another for storing CustomerInfo(user of type customer).
class User(AbstractBaseUser):
"""
This is a class for user table which overrides functionalities of default django user model.
Attributes:
name (CharField): Name of a user.
email (EmailField): Email address of a user.
mobile (CharField): Phone number of a user.
date_joined (CharField): When a user was added.
last_login (CharField): Last login date time of a user.
is_admin (CharField): If user is a admin or not.
is_active (CharField): If user is active or not.
is_staff (CharField): If user is staff or not.
is_superuser (CharField): If user is a superuser or not.
role (OneToOneField): One to one relationship with role table.
"""
name = models.CharField(max_length=80)
email = models.EmailField(max_length=255, unique=True)
mobile = models.CharField(
validators=[
RegexValidator(
regex=r"^\d{10,14}$",
message="Phone number must be entered in format: '[phone]'. Up to 14 digits allowed.",
)
],
max_length=15,
unique=True,
)
role = models.ForeignKey(Role, on_delete=models.SET_NULL, null=True)
drivers = models.ManyToManyField(
"self", through="DispatcherDriver", symmetrical=False
)
date_joined = models.DateTimeField(auto_now_add=True)
last_login = models.DateTimeField(auto_now=True)
is_admin = models.BooleanField(default=False)
is_active = models.BooleanField(default=True)
is_staff = models.BooleanField(default=False)
is_superuser = models.BooleanField(default=False)
created_at = models.DateTimeField(auto_now_add=True, null=True, blank=True)
updated_at = models.DateTimeField(auto_now=True, null=True, blank=True)
USERNAME_FIELD = "mobile"
REQUIRED_FIELDS = ["email", "name"]
objects = UserManager()
class Meta:
db_table = "users"
def __str__(self):
return self.name
# For checking permissions. to keep it simple all admin have ALL permissons
def has_perm(self, perm, obj=None):
return self.is_admin
# Does this user have permission to view this app? (ALWAYS YES FOR SIMPLICITY)
def has_module_perms(self, app_label):
return True
#receiver(post_save, sender=settings.AUTH_USER_MODEL)
def create_auth_token(sender, instance=None, created=False, **kwargs):
if created:
Token.objects.create(user=instance)
class CustomerInfo(models.Model):
customer = models.OneToOneField(
User, on_delete=models.CASCADE, primary_key=True, related_name="customer_info"
)
company_name = models.CharField(max_length=255)
class Meta:
db_table = "customer_info"
def __str__(self):
return self.company_name
CustomerInfo model has OneToOneField mentioned in the model. How can I access CustomerInfo of a User model using reverse relationship?

Answer 1

Suppose, you has User's instance user then you can fetch customer_info as
from django.core.exceptions import ObjectDoesNotExist
try:
customer_info = user.customer_info
except ObjectDoesNotExist:
print("There is no customer info here.")
Reference - https://docs.djangoproject.com/en/3.1/topics/db/examples/one_to_one/

Answer 2

Try:
myuser = User.objects.create(email="..", name="..", password="1223")
profile = CustomerInfo.objects.create(customer=myuser)
company_name = myuser.customer_info.company_name