How to make proper model hierarchy in Django?

Question

Django

I have cocktail, ingredient and serving models. I don’t understand how to make it so that when choosing an ingredient, you need to specify its portion. How should models be organized so that everything works correctly? At the moment the models look like this:

from django.db import models


class Cocktail(models.Model):
    title = models.CharField(max_length=50, db_index=True, verbose_name='Название')
    ingredients = models.ManyToManyField('Ingredient', verbose_name='Ингредиент')
    # Stars or rating = Many to One

    def __str__(self):
        return f"{self.title}: id = {self.id} "

    class Meta:
        verbose_name_plural = 'Коктейли'
        verbose_name = 'Коктейль'


class Ingredient(models.Model):
    # portion = models.CharField(max_length=6, choices=PORTIONS, blank=True)

    title = models.CharField(max_length=30, db_index=True, verbose_name='Название')
    portion = models.ForeignKey('Portion', null=True, blank=True, on_delete=models.SET_NULL)

    def __str__(self):
        return self.title

    class Meta:
        verbose_name_plural = 'Ингредиенты'
        verbose_name = 'Ингредиент'


class Portion(models.Model):
    PORTIONS = (
        ('50 ml', 'одна часть'),
        ('75 ml', 'полторы части'),
        ('100 ml', 'две части'),
        ('150 ml', 'три части'),
    )
    portion = models.CharField(max_length=6, choices=PORTIONS, blank=True, verbose_name='Порция')

    def __str__(self):
        return self.portion

    class Meta:
        verbose_name_plural = 'Порции'
        verbose_name = 'Порция'

Answer 1

example of how to do it https://docs.djangoproject.com/en/4.0/topics/db/mo...