Django-使用外键检索多层嵌套字段
我正在努力编写一个Django GET,它返回以下外观响应:Django-使用外键检索多层嵌套字段,django,django-models,django-serializer,Django,Django Models,Django Serializer,我正在努力编写一个Django GET,它返回以下外观响应: { "lists": [ { "id": "123", "list_order": [ { "id": "123_1", "order": 1, "list_id": "123", "item_id": 9876,
{
"lists": [
{
"id": "123",
"list_order": [
{
"id": "123_1",
"order": 1,
"list_id": "123",
"item_id": 9876,
"item": {
"id": 9876,
"name": "item1",
"location": "California"
}
},
{
"id": "123_2",
"order": 2,
"list_id": "123",
"item_id": 2484,
"item": {
"id": 2484,
"name": "item2",
"location": "California"
}
}
],
"updated_date": "2018-03-15T00:00:00Z"
}
]
}
给定列表id,响应返回列表上的基本信息(“id”、“更新日期”)以及列表中项目的顺序。在列表顺序中的每个项目中,它还获取相关的项目详细信息(嵌套在“项目”中)。我能够在没有“项目”详细信息(“id”、“名称”、“位置”字段)的情况下获得此响应,并且没有错误:
{
"lists": [
{
"id": "123",
"list_order": [
{
"id": "123_1",
"order": 1,
"list_id": "123",
"item_id": 9876
},
{
"id": "123_2",
"order": 2,
"list_id": "123",
"item_id": 2484
}
],
"updated_date": "2018-03-15T00:00:00Z"
}
]
}
同样没有错误,我可以毫无问题地检索第一个嵌套级别。问题是如何在每个“列表顺序”中显示“项目”信息。下面是我的模型、序列化程序和视图
型号.py
序列化程序.py
视图.py
我是Django的新手,喜欢它目前提供的服务,尽管我可能想用“SQL”的方式来做这件事。我已经读过select_related()和prefetch_related(),但不确定如何将其应用到这个案例中。非常感谢您提供的任何帮助,如果还有其他信息,请告诉我。在您的
列表OrderSerializer
中,您正在尝试对项进行序列化。在ListOrder
模型中,您使用了字段名item\u id
class Lists(models.Model):
id = models.CharField(null=False, primary_key=True, max_length=900)
updated_date = models.DateTimeField(blank=True, null=True)
class Meta:
managed = False
db_table = 'tbl_lists'
class Items(models.Model):
id = models.BigIntegerField(primary_key=True)
name = models.TextField(blank=True, null=True)
location = models.TextField(blank=True, null=True)
class Meta:
managed = False
db_table = 'tbl_items'
class ListOrder(models.Model):
id = models.CharField(null=False, primary_key=True, max_length=900)
list_id = models.ForeignKey(Lists, db_column='list_id', related_name='list_order')
item_id = models.ForeignKey(Items, db_column='item_id', related_name='items')
order = models.BigIntegerField(blank=True, null=True)
class Meta:
managed = False
db_table = 'tbl_list_order'
class ItemsSerializer(serializers.ModelSerializer):
class Meta:
model = Items
fields = '__all__'
class ListOrderSerializer(serializers.ModelSerializer):
item = ItemsSerializer(many=False, read_only=True)
class Meta:
model = ListOrder
fields = '__all__'
class ListsSerializer(serializers.ModelSerializer):
list_order = ListOrderSerializer(many=True, read_only=True)
class Meta:
model = Lists
fields = '__all__'
class ListsViewSet(generics.ListCreateAPIView):
"""
API endpoint that returns a list with its meta-information
"""
queryset = Lists.objects.all()
serializer_class = ListsSerializer
def get_queryset(self):
list_id = self.kwargs['list_id']
filters = [Q(id=list_id)]
return Lists.objects.filter(*filters)
def list(self, request, list_id):
queryset = self.get_queryset()
list_serializer = ListsSerializer(queryset, many=True)
return Response({ 'lists': list_serializer.data })
解决方案:
在ListOrderSerializer
中:
class ListOrderSerializer(serializers.ModelSerializer):
item_id = ItemsSerializer(many=False, read_only=True)
...