Django Rest API ManyToMany 在 API 中没有给出任何 []

Question

目前我尝试从我的 API 获取食谱。我有一个包含两个表的数据库，其中一个包含食谱及其 ID，但没有成分，另一个表包含成分和食谱 ID。现在我找不到API“组合”这些的方法。也许是因为我在我的成分模型中添加了相关名称的配方 ID，但我必须这样做，否则会发生此错误：

ERRORS:
recipes.Ingredients.recipeid: (fields.E303) Reverse query name for 'Ingredients.recipeid' clashes with field name 'Recipe.ingredients'.
        HINT: Rename field 'Recipe.ingredients', or add/change a related_name argument to the definition for field 'Ingredients.recipeid'.

型号

from django.db import models

class Ingredients(models.Model):
    ingredientid = models.AutoField(db_column='IngredientID', primary_key=True, blank=True)
    recipeid = models.ForeignKey('Recipe', models.DO_NOTHING, db_column='recipeid', blank=True, null=True, related_name='+')
    amount = models.CharField(blank=True, null=True, max_length=100)
    unit = models.CharField(blank=True, null=True, max_length=100)
    unit2 = models.CharField(blank=True, null=True, max_length=100)
    ingredient = models.CharField(db_column='Ingredient', blank=True, null=True, max_length=255)
    
    class Meta:
        managed = True
        db_table = 'Ingredients'  

class Recipe(models.Model):
    recipeid = models.AutoField(db_column='RecipeID', primary_key=True, blank=True)  # Field name made lowercase.
    title = models.CharField(db_column='Title', blank=True, null=True, max_length=255)  # Field name made lowercase.
    preperation = models.TextField(db_column='Preperation', blank=True, null=True)  # Field name made lowercase.
    images = models.CharField(db_column='Images', blank=True, null=True, max_length=255)  # Field name made lowercase.
    #ingredients = models.ManyToManyField(Ingredients) 
    ingredients = models.ManyToManyField(Ingredients, related_name='recipes')
    class Meta:
        managed = True
        db_table = 'Recipes'

如果没有问题，则必须在序列化程序或视图中。

序列化器

class IngredientsSerializer(serializers.ModelSerializer):
   # ingredients = serializers.CharField(source='ingredients__ingredients')

    class Meta:
        model = Ingredients
        fields = ['ingredient','recipeid']

class FullRecipeSerializer(serializers.ModelSerializer):

    ingredients = IngredientsSerializer(many=True)

    class Meta:
        model = Recipe
        fields = ['title','ingredients']

查看

class FullRecipesView(generics.ListCreateAPIView):
    serializer_class = FullRecipeSerializer
    permission_classes = [
        permissions.AllowAny
    ]
    queryset = Recipe.objects.all()

This is at the moment my output 但我想要例如id 为 0 的配方和所有配方 id 为 0 的成分。 我真的希望你能帮助我。非常感谢！

Answer 1

来自ForeignKey.related_name的文档，

如果您不希望 Django 创建反向关系，请将 related_name 设置为 '+' 或以 '+' 结束。

因此，将 Ingredients.recipeid 字段的 related_name 更改为

class Ingredients(models.Model):
    # rest of the fields
    recipeid = models.ForeignKey(
        'Recipe',
        models.DO_NOTHING,
        db_column='recipeid',
        blank=True,
        null=True,
        related_name="ingredients_ref" # Changed the related name 
    )

然后，使用python manage.py makemigrations 和python manage.py migrate 迁移数据库

然后，将您的 FullRecipeSerializer 类更新为，

class FullRecipeSerializer(serializers.ModelSerializer):
    ingredients_forward = IngredientsSerializer(many=True, source="ingredients")
    ingredients_backward = IngredientsSerializer(many=True, source="ingredients_ref")

    class Meta:
        model = Recipe
        fields = ['title', 'ingredients_forward', 'ingredients_backward']

请注意，这里我添加了两个名为ingredients_forward 和ingredients_backward 的字段，因为Recipe 和Ingredients 之间存在两种类型的关系，我不确定您要查找的是哪一种。