Code demonstrating how to effectively use django's models.JSONField to achieve flexibility in modelling data

transactions.py

from typing import Optional

from django.core.exceptions import ValidationError
from django.db import models
from pydantic import BaseModel, EmailStr, PydanticValidationError


class CreditCardSchema(BaseModel):
    number: str
    expiry_month: int
    expiry_year: int
    cvv: str


class PayPalSchema(BaseModel):
    email: EmailStr


class CryptoSchema(BaseModel):
    wallet_address: str
    network: Optional[str] = None


class BillingAddressSchema(BaseModel):
    street: str
    city: str
    country: str
    postal_code: str
    state: Optional[str] = None


class PaymentMethodSchema(BaseModel):
    credit_card: Optional[CreditCardSchema] = None
    paypal: Optional[PayPalSchema] = None
    crypto: Optional[CryptoSchema] = None
    billing_address: Optional[BillingAddressSchema] = None


class Currencies(models.TextChoices):
    USD = "USD", "US Dollar"
    EUR = "EUR", "Euro"
    GBP = "GBP", "British Pound"
    BTC = "BTC", "Bitcoin"


class TransactionStatuses(models.TextChoices):
    PENDING = "PENDING", "Pending"
    COMPLETED = "COMPLETED", "Completed"
    FAILED = "FAILED", "Failed"
    REFUNDED = "REFUNDED", "Refunded"


def payment_method_validator(value: Optional[dict]):
    if value is None:
        return
    try:
        PaymentMethodSchema(**value)
    except PydanticValidationError as e:
        raise ValidationError(e.errors())


class Transaction(models.Model):
    processor_reference = models.CharField(max_length=96)
    status = models.CharField(max_length=50, choices=TransactionStatuses.choices)
    transaction_date = models.DateTimeField(auto_now_add=True)
    amount = models.DecimalField(max_digits=8, decimal_places=2)
    currency = models.CharField(
        max_length=10,
        choices=Currencies.choices,
        null=True,
    )
    payment_method = models.JSONField(
        validators=[payment_method_validator], null=True, blank=True
    )
    
   def save(self, *args, **kwargs):
        self.full_clean()
        super().save(*args, **kwargs)