django-tastypie和许多到许多“直通”关系 [英] django-tastypie and many to many "through" relationships

问题描述

在Django和Deliciouspie中，我试图弄清楚如何正确处理通过关系，例如在这里找到的： https://docs.djangoproject.com/zh-CN/dev/topics/db/models/#extra

In Django and Tastypie I'm attempting to figure out how to properly deal with Many to Many "through" relationships, like those found here: https://docs.djangoproject.com/en/dev/topics/db/models/#extra-fields-on-many-to-many-relationships

以下是我的示例模型：

class Ingredient(models.Model):
    name = models.CharField(max_length=100)
    description = models.TextField()

class RecipeIngredients(models.Model):
    recipe = models.ForeignKey('Recipe')
    ingredient = models.ForeignKey('Ingredient')
    weight = models.IntegerField(null = True, blank = True)

class Recipe(models.Model):
    title = models.CharField(max_length=100)
    ingredients = models.ManyToManyField(Ingredient, related_name='ingredients', through='RecipeIngredients', null = True, blank = True)

现在我的api.py文件：

Now my api.py file:

class IngredientResource(ModelResource):
    ingredients = fields.ToOneField('RecipeResource', 'ingredients', full=True)

    class Meta:
        queryset = Ingredient.objects.all()
        resource_name = "ingredients"


class RecipeIngredientResource(ModelResource):
    ingredient = fields.ToOneField(IngredientResource, 'ingredients', full=True)
    recipe = fields.ToOneField('RecipeResource', 'recipe', full=True)

    class Meta:
        queryset= RecipeIngredients.objects.all()


class RecipeResource(ModelResource):
    ingredients = fields.ToManyField(RecipeIngredientResource, 'ingredients', full=True)

class Meta:
    queryset = Recipe.objects.all()
    resource_name = 'recipe'

我试图基于以下示例创建代码： http://pastebin.com/L7U5rKn9

I'm trying to base my code on this example: http://pastebin.com/L7U5rKn9

不幸的是，使用此代码，我收到此错误：

Unfortunately, with this code I get this error:

"error_message": "'Ingredient' object has no attribute 'recipe'"

有人知道这里发生了什么吗？或者如何在RecipeIngredientResource中包含成分名称？谢谢！

Does anyone know what's happening here? Or how I can include the name of the ingredient in the RecipeIngredientResource? Thanks!

编辑：

我可能自己也发现了错误。 ToManyField应该针对成分而不是RecipeIngredient。我会看看这是否起作用。

I may have found the error myself. ToManyField should be directed toward Ingredient and not RecipeIngredient. I'll see if this does the job.

编辑：

新错误..有什么想法吗？
对象的属性'title'为空，不允许使用默认值或null值。

New error.. any ideas? The object '' has an empty attribute 'title' and doesn't allow a default or null value.

推荐答案

您提到了：

我可能自己也发现了错误。 ToManyField应该针对成分而不是RecipeIngredient。我会看看这是否能解决问题。

I may have found the error myself. ToManyField should be directed toward Ingredient and not RecipeIngredient. I'll see if this does the job.

虽然[Tastypie M2M] （ http://blog.eugene-yeo.in/django-tastypie-manytomany-through.html ）（旧博客离线： https://github.com/9gix/eugene-yeo.in/blob/master/content/web/django-tastiepie-m2m.rst ）

There's a better approach though [Tastypie M2M](http://blog.eugene-yeo.in/django-tastypie-manytomany-through.html) (old blog is offline: https://github.com/9gix/eugene-yeo.in/blob/master/content/web/django-tastiepie-m2m.rst)

简而言之，我对配料使用了 ToManyField 而不是 ToManyField ThroughModel 。并将自定义属性 kwargs设为返回 ThroughModel 查询集的回调函数。

In short summary, Instead of ToManyField to Ingredients, I use ToManyField toward the ThroughModel. And customize the attribute kwargs to be a callback function that return the ThroughModel Queryset.

这个答案是很久以前做出的。不知道它是否仍然有用。

This answer is made long ago. Not sure if it is still useful.

这篇关于django-tastypie和许多到许多“直通”关系的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！