nummi/nummi/main/models.py

import uuid
from django.db import models


class Transaction(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=256)
    description = models.TextField()
    value = models.DecimalField(max_digits=12, decimal_places=2)
    date = models.DateField()

    def __str__(self):
        return f"{self.date} {self.name}: {self.value}€"


class Invoice(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=256)
    file = models.FileField(upload_to="invoices/")
    transaction = models.ForeignKey(Transaction, on_delete=models.CASCADE)

    def __str__(self):
        return f"{self.name}: {self.transaction}"