django-models

Django Models

Core Requirements

For every model, we:

• Use explicit db_table names (pluralized)
• Include helpful docstrings
• Use proper field types for financial data (DecimalField for money)
• Use help_text only when the field purpose isn't immediately clear
• Add verbose_names where they improve readability

Model Structure

from django.db import models
from decimal import Decimal

class Order(models.Model):
    """Represents a customer order

    Tracks order details, payment status, and fulfillment
    """

    customer = models.ForeignKey('Customer', on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)
    total_amount = models.DecimalField(
        max_digits=18,
        decimal_places=2,
        help_text="Total order amount in USD"
    )
    status = models.CharField(max_length=20, default='pending')

    class Meta:
        db_table = "orders"
        verbose_name_plural = "orders"
        ordering = ['-created_at']

    def __str__(self):
        return f"Order #{self.id} - {self.customer}"

    @property
    def is_complete(self) -> bool:
        return self.status == 'fulfilled'

Financial Fields

We always use DecimalField for amounts: max_digits=18, decimal_places=8 for crypto, max_digits=18, decimal_places=2 for fiat.

Query Optimization

We use select_related() for foreign keys, prefetch_related() for reverse relations, and add indexes for frequently queried fields.

Field Guidelines

We use auto_now_add=True for creation timestamps, auto_now=True for update timestamps, and blank=True, null=True for truly optional fields.