How to use reverse relation in my query?(django)

Welcome to Programming Tutorial official website. Today - we are going to cover how to solve / find the solution of this error How to use reverse relation in my query?(django) on this date .

I’m trying to make a query to show all the branches which have the food. I’ve tried a lot but I can’t make it work. Could someone help me?

Here are my models:

class Branch(models.Model):
    name = models.CharField(max_length=100)
    created = models.DateTimeField(auto_now_add=True)
    is_main = models.BooleanField()
    description = models.TextField(max_length=500)

    food_restaurant_category = models.OneToOneField(FoodRestaurantCategory, on_delete=models.CASCADE)
    restaurant = models.ForeignKey(Restaurant, on_delete=models.CASCADE)
    branch_address = models.OneToOneField(BranchAddress, on_delete=models.CASCADE)
    manager = models.OneToOneField("accounts.Staff", on_delete=models.CASCADE)


class Food(models.Model):
    name = models.CharField(max_length=100)
    image = models.ImageField(upload_to=upload_path)
    description = models.TextField(max_length=500)
    created = models.DateTimeField(auto_now_add=True)

    meal_category = models.ManyToManyField(MealCategory, related_name="meal")
    food_restaurant_category = models.ManyToManyField(FoodRestaurantCategory, related_name="food_cat")

class Menu(models.Model):
    inventory = models.PositiveIntegerField()
    price = models.DecimalField(validators=[MinValueValidator(0.0)], max_digits=10, decimal_places=1)

    food = models.ForeignKey(Food, on_delete=models.CASCADE, related_name="food_rel")
    branch = models.ForeignKey(Branch, on_delete=models.CASCADE, related_name="branch_rel")

Answer

You can obtain the Branches for which there is a Menu that links to a Food object food with:

Branch.objects.filter(branch_rel__food=food)

It however does not seem to make much sense to specify related_name='food_rel' and related_name='branch_rel' since this is the name of the relation in reverse, likely related_name='menus', in that case you filter with Branch.objects.filter(menus__food=food).