使用 django-rest-framework 序列化程序检索外键值 [英] Retrieving a Foreign Key value with django-rest-framework serializers

问题描述

我正在使用 django rest 框架来创建 API.我有以下型号:

I'm using the django rest framework to create an API. I have the following models:

class Category(models.Model):
    name = models.CharField(max_length=100)

    def __unicode__(self):
        return self.name


class Item(models.Model):
    name = models.CharField(max_length=100)
    category = models.ForeignKey(Category, related_name='items')

    def __unicode__(self):
        return self.name

要为我要做的类别创建序列化程序:

To create a serializer for the categories I'd do:

class CategorySerializer(serializers.ModelSerializer):
    items = serializers.RelatedField(many=True)

    class Meta:
        model = Category

...这将为我提供:

[{'items': [u'Item 1', u'Item 2', u'Item 3'], u'id': 1, 'name': u'Cat 1'},
 {'items': [u'Item 4', u'Item 5', u'Item 6'], u'id': 2, 'name': u'Cat 2'},
 {'items': [u'Item 7', u'Item 8', u'Item 9'], u'id': 3, 'name': u'Cat 3'}]

我将如何从 Item 序列化程序获取反向信息，即:

How would I go about getting the reverse from an Item serializer, ie:

[{u'id': 1, 'name': 'Item 1', 'category_name': u'Cat 1'},
{u'id': 2, 'name': 'Item 2', 'category_name': u'Cat 1'},
{u'id': 3, 'name': 'Item 3', 'category_name': u'Cat 1'},
{u'id': 4, 'name': 'Item 4', 'category_name': u'Cat 2'},
{u'id': 5, 'name': 'Item 5', 'category_name': u'Cat 2'},
{u'id': 6, 'name': 'Item 6', 'category_name': u'Cat 2'},
{u'id': 7, 'name': 'Item 7', 'category_name': u'Cat 3'},
{u'id': 8, 'name': 'Item 8', 'category_name': u'Cat 3'},
{u'id': 9, 'name': 'Item 9', 'category_name': u'Cat 3'}]

我已经阅读了关于反向关系 对于其余框架，但这似乎与非反向字段的结果相同.我是否遗漏了一些明显的东西?

I've read through the docs on reverse relationships for the rest framework but that appears to be the same result as the non-reverse fields. Am I missing something obvious?

推荐答案

只需使用相关字段，无需设置many=True.

Just use a related field without setting many=True.

注意，同样因为你想要名为category_name的输出，但实际的字段是category，所以你需要在上使用source参数序列化器字段.

Note that also because you want the output named category_name, but the actual field is category, you need to use the source argument on the serializer field.

以下应该给你你需要的输出......

The following should give you the output you need...

class ItemSerializer(serializers.ModelSerializer):
    category_name = serializers.RelatedField(source='category', read_only=True)

    class Meta:
        model = Item
        fields = ('id', 'name', 'category_name')

这篇关于使用 django-rest-framework 序列化程序检索外键值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！