Cannot see foreign key values in the template - django

Question

This is my 2nd week learning Django. I'm trying to get comfortable with Django Template Language. I'm trying to make an Inventory app with 4 models. The views for them are class-based.
The templates for Ingredient and Menu work as expected. However, I'm struggling with trying to loop through values from the Purchase model which has a foreign key field 'menu_item'. The template is not showing anything from the for loop. I've referred numerous articles here to find most of them use function-based views. I've tried using {% for purchase in purchase_set %}, {% for purchase in purchase_set.all %}. I know the object to iterate over is a query-set. I cannot figure out what to do?
MODELS.PY
from django.db import models
# Create your models here.
class Ingredient(models.Model):
Pounds = 'lbs'
Ounces = 'oz'
Grams = 'gms'
Eggs = 'eggs'
Piece = 'piece'
Litre = 'litre'
unit_choices = [(Pounds, 'lbs'),
(Ounces, 'ounces'),
(Grams, 'grams'),
(Eggs, 'eggs'),
(Piece, 'piece'),
(Litre, 'litre')]
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=50)
unit_price = models.FloatField(default=0.0)
quantity = models.FloatField(default=0.0)
unit = models.CharField(max_length=10, choices=unit_choices)
class Meta:
ordering = ['id']
def __str__(self):
return self.name
class MenuItem(models.Model):
id = models.AutoField(primary_key=True)
title = models.CharField(max_length=50)
price = models.FloatField(default=0.0)
class Meta:
ordering = ['id']
def __str__(self):
return self.title
class RecipeRequirement(models.Model):
menu_item = models.ForeignKey(MenuItem, on_delete=models.CASCADE)
ingredient = models.ForeignKey(Ingredient, on_delete=models.CASCADE)
quantity = models.FloatField(default=0.0)
def __str__(self):
return self.menu_item.title
class Purchase(models.Model):
menu_item = models.ForeignKey(MenuItem, on_delete=models.CASCADE)
timestamp = models.DateTimeField()
id = models.AutoField(primary_key=True)
class Meta:
ordering = ['id']
def __str__(self):
return self.menu_item.title
VIEWS.PY:
from django.shortcuts import render
from .models import Ingredient, MenuItem, RecipeRequirement, Purchase
from django.views.generic import ListView
def home(request):
return render(request, 'inventory/home.html')
class IngredientView(ListView):
model = Ingredient
template_name = 'inventory/ingredients.html'
class PurchaseView(ListView):
model = Purchase
template_name = 'inventory/purchases.html'
class MenuView(ListView):
model = MenuItem
template_name = 'inventory/menu.html'
PURCHASES.HTML
<h3>This is purchases page.</h3>
{% block content %}
<table>
{% for purchase in purchase_set.all %}
<tr>
<td>{{ purchase.title }}</td>
</tr>
{% endfor %}
</table>
{% endblock %}

Answer 1

The title field you are trying to show is in MenuItem model that is used as foreignkey in Purchase model with menu_item field. ListView class returns to context yours purchases in object_list key. So in Your purchases.html template:
<h3>This is purchases page.</h3>
{% block content %}
<table>
{% for purchase in object_list %}
<tr>
<td>{{ purchase.menu_item.title }}</td>
</tr>
{% endfor %}
</table>
{% endblock %}
PS. This `purchase_set' is referring to reverse relationship. So if you would want to show all purchases of MenuItem you would do:
{% for item in menuitems %}
<h1>{{ item }}</h1>
{% for purchase in item.purchase_set.all %}
<p>{{ purchase.timestamp }}</p>
{% endfor %}
{% endfor %}