我想创建一个Django过滤器,该过滤器查找饮料中包含的成分。但是,没有其他成分存在,只有我输入的成分。
我承认我有可乐,杜松子酒和补品。
以下饮料应该回来:
朗姆可乐没有回来,因为我没有朗姆酒。
我如何在Django中做到这一点?我有一个数据库,名为TankAllocation。我在那里输入每个储罐的配料。
我尝试使用Django过滤器,但是那里没有正确的饮料。
也许我可以比较成分表和储罐表中成分的查询集并删除重复的条目,然后使用以下命令启动非等价查询:from django.db.models importQ。但是如何在以下位置删除重复的条目:查询集?对于新的过滤器查询,两个条目都应删除。
Models.py
from django.db import models
class Drink(models.Model):
name = models.CharField(max_length=256, unique=True)
description = models.TextField()
image_path = models.ImageField(upload_to=".\images")
slug = models.SlugField(unique=True)
ingredient = models.ManyToManyField('Ingredient', through='IngredientRatio', related_name='mischung',)
def __str__(self):
return self.name
class Ingredient(models.Model):
name = models.CharField(max_length=256, unique=True)
alcohol = models.BooleanField()
def __str__(self):
return self.name
class IngredientRatio(models.Model):
quantity = models.DecimalField(max_digits=4, decimal_places=2)
ingredient = models.ForeignKey('Ingredient', on_delete=models.CASCADE)
drink = models.ForeignKey('Drink', on_delete=models.CASCADE)
def __str__(self):
return "{0}: {1} : {2}".format(self.drink.name, self.ingredient.name, self.quantity)
class TankAllocation(models.Model):
name = models.CharField(max_length=8, unique=True)
allocation = models.ForeignKey('Ingredient', on_delete=models.CASCADE, default='NULL', related_name='ingredients')
def __str__(self):
return "{0}: {1}".format(self.allocation.name, self.name)
谢谢您的帮助,我在编程方面是个新手:)))
答案 0 :(得分:0)
我不确定我是否完全理解,但是这样的事情应该起作用:
ingredients = ['Cola', 'Gin', 'Tonic']
drinks = Drink.objects.filter(ingredient__name__in=ingredients).distinct()
答案 1 :(得分:0)
我现在找到了解决方案:)
import operator
from functools import reduce
from django.db.models import Q
from .models import Ingredient, TankAllocation, Drink
def drinkFilter():
ingredient_list_nq = []
ingredient_obj_list = Ingredient.objects.all()
ingredients = [ingredient.name for ingredient in ingredient_obj_list]
tanks = TankAllocation.objects.all()
tank_ingredients = [tank.allocation.name for tank in tanks]
for ingredient in ingredients:
if ingredient not in tank_ingredients:
ingredient_list_nq.append(ingredient)
new_filter = []
for ingredient in ingredient_list_nq:
new_filter.append(~Q(ingredient__name=ingredient))
print(new_filter)
return new_filter
def get_drinks():
filter = drinkFilter()
return Drink.objects.filter(reduce(operator.and_, filter))