[英]Django Rest Framework - Filter fields of nested relationships
I want to return a nested representation of Customer
with Image
objects, where a Customer
can have many Images
.我想返回带有Image
对象的Customer
的嵌套表示,其中Customer
可以有很多Images
。
Currently, the GET request returns a list of ALL images from the Image
queryset for each Customer
object as shown below.目前,GET 请求从每个Customer
object 的Image
查询集中返回所有图像的列表,如下所示。 How can I show only related Image
(s) for each Customer
object in a list instead?我怎样才能在列表中只显示每个Customer
object 的相关Image
?
# The 'images' field currently returns all images rather than related images to the customer id.
[
{
'id': 1,
'name': 'John Doe',
'images': [
{'id': 1, 'name': 'foo.jpg', 'customer': 1},
{'id': 2, 'name': 'bar.jpg', 'customer': 2},
{'id': 3, 'name': 'foobar.jpg', 'customer': 3},
...
]
},
{
'id': 2,
'name': 'Jane Doe',
'images': [
{'id': 1, 'name': 'foo.jpg', 'customer': 1},
{'id': 2, 'name': 'bar.jpg', 'customer': 2},
{'id': 3, 'name': 'foobar.jpg', 'customer': 3},
...
]
},
...
]
This is my current setup这是我目前的设置
Example Models示例模型
class Customer(models.Model):
name = models.CharField()
class Image(models.Model):
name = models.CharField()
customer = models.ForeignKey(
Customer, on_delete=models.CASCADE)
Example Serializers示例序列化程序
class CustomerSerializer(serializers.ModelSerializer):
# My Customer nested relationship is expressed using ImageSerializer as a field
images = ImageSerializer(many=True)
class Meta:
model = Customer
fields = ('id', 'name', 'images')
read_only_fields = ('id',)
class ImageSerializer(serializers.ModelSerializer):
class Meta:
model = Image
fields = '__all__'
read_only_fields = ('id',)
Please let me know if my question is unclear and I will update my question.如果我的问题不清楚,请告诉我,我会更新我的问题。 Thank you.谢谢你。
You need to use the related name as the field for the reverse foreign key.您需要使用相关名称作为反向外键的字段。
In your case this would be;在您的情况下,这将是;
class CustomerSerializer(serializers.ModelSerializer):
class Meta:
model = Customer
fields = ('id', 'name', 'image_set')
read_only_fields = ('id',)
Consider it like a reverse FK query - Customer.objects.first().image_set.all()
将其视为反向 FK 查询 - Customer.objects.first().image_set.all()
DRF Docs on this are here;关于此的 DRF 文档在这里; Reverse Relations 反向关系
Django docs on reversing relationships are here Django 反转关系的文档在这里
Using the _set
reverse lookup like this is the django default.像这样使用_set
反向查找是 django 默认值。 It's possible that you may add your own related_name
to a relationship.您可以将自己的related_name
添加到关系中。
An example from the django docs;来自 django 文档的示例;
# Declare the ForeignKey with related_query_name
class Tag(models.Model):
article = models.ForeignKey(
Article,
on_delete=models.CASCADE,
related_name="tags",
related_query_name="tag",
)
name = models.CharField(max_length=255)
# That's now the name of the reverse filter
Article.objects.filter(tag__name="important")
For your example you might add something like;对于您的示例,您可以添加类似的内容;
class Image(models.Model):
name = models.CharField()
customer = models.ForeignKey(
Customer,
on_delete=models.CASCADE,
related_name="images"
)
The django default of Customer.image_set
will still work, but you can then do Customer.images.all()
because you've defined that related_name
for the relationship. Customer.image_set
的 django 默认值仍然有效,但您随后可以执行Customer.images.all()
,因为您已经为关系定义了related_name
。
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