Querying django models to include and exclude items - django

Question

I currently have 2 models as such
class Recipe(models.Model):
account = models.ForeignKey(CustomUser, on_delete=models.CASCADE, null=True, blank=True)
name = models.TextField(null=True, blank=True)
slug = models.SlugField(null=False, blank=True, unique=True)
image_path = models.ImageField(upload_to=MEDIA_URL, null=True, blank=True)
description = models.TextField(null=True, blank=True)
date_added = models.DateField(auto_now_add=True)
class RecipeIngredients(models.Model):
recipe = models.ForeignKey(Recipe, on_delete=models.CASCADE, null=True)
ingredient = models.TextField(null=True, blank=True)
quantity = models.CharField(max_length=10, null=True, blank=True)
type = models.CharField(max_length=50, null=True, blank=True)
I am trying to do a query where if I have a list of say 2 or more items, say
ingredients = ["egg", "bacon", "rice"]
That it returns to me only the recipes that have exactly egg, bacon, and rice, or less.
I was able to do this in a hacky way, but it is really slow and not using the ORM correctly I feel.
ingredients = ["egg", "bacon", "rice"]
results = []
recipes = []
for i in ingredients:
r = RecipeIngredients.objects.filter(ingredient__icontains=i)
results.append(r)
for result in results:
for r in result:
recipes.append(r.recipe)
for r in recipes:
recipeingredients = r.recipeingredients_set.all()
for ri in recipeingredients:
ingredient = ri.ingredient
if ingredient not in ingredients:
try:
recipes.remove(r)
except:
print(r)
print("end of recipe")
Any help on how to make this a more correct query would be appreciated.

Answer 1

You can use raw sql, something like this:
recipe_list = Recipe.objects.raw('select a.*
from app_Recipe a
inner join app_RecipeIngredients b
on a.id = b.recipe_id and b.ingredient in ("egg", "bacon", "rice")
group by a.*
having count(*) >= 2')
maybe replace app_ with your project name, replace a.* with list of column names.