Django与另一个领域的许多关系 [英] Django Many to Many Relationship With Another Field

问题描述

我有两种型号，配方和成分。食谱模型与Ingredients具有多重关系，但我也需要能够指定成分的数量。我的模型目前看起来像：

I have two models, Recipe and Ingredient. The Recipe model has a manytomany relationship with Ingredients, but I also need to be able to specify the quantity of the ingredients. My models currently look like:

class Ingredient(models.Model):
    name = models.CharField(max_length="256", db_index=True, null=True)

class Recipe(models.Model):
    ...
    ingredients = models.ManyToManyField(Ingredient, related_name="RecipeIngredients", db_index=True)

但显然，每个配方的每个配料数量都会不一样。所以我需要这样做：

But obviously each recipe will have different quantities of each ingredient. So I need to be able to do something like:

cakeRecipe = Recipe.objects.get(pk=1)
flour = Ingredient.objects.get(pk=2)
cakeRecipe.ingredients.add(flour, '200 grams')

但我不知道如何。任何帮助将不胜感激。谢谢：）

But I don't know how. Any help would be greatly appreciated. Thanks :)

推荐答案

您需要按照多对多关系的额外字段：

class RecipeIngredient(models.Model):
    recipe = models.ForeignKey('Recipe')
    ingredient = models.ForeignKey('Ingredient')
    quantity = models.CharField(max_length=200)

class Recipe(models.Model):
    ingredients = models.ManyToManyField(Ingredient, through=RecipeIngredient)

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