Django使用prefech

• 前言
• • Models
  • Serializers
  • Views
  • 数据库
  • 结果

由于没有使用Django的templates，而仅仅是将Django作为后端，因此使用rest_framework来实现resful风格的API，在开发过程中将place作为image的外键，希望达到的目标是在获取所有place信息的同时，获取它相关的image，通过image中的Foreignkey即place_id反向获取多个image对象。通过不断探索，终于是实现了这个效果。现在看来这个实现过程非常简单，只是苦于之前缺少相关知识，久久无法实现，特此记录，希望能帮到有需要的人。

#地点类
class Place(models.Model):
    id = models.CharField(max_length=32, primary_key=True)
    name = models.CharField(max_length=255, blank=True, null=True)
    
#图片类
class PlaceImage(models.Model):
    id = models.CharField(max_length=32, primary_key=True)
    name = models.CharField(max_length=255, blank=True, null=True)
    place = models.ForeignKey(Place, on_delete=models.CASCADE, related_name='place_image')
    

class PlaceImageSerializer(serializers.ModelSerializer):
    class Meta:
        model = PlaceImage
        fields = ('id', 'name') 
        
class PlaceSerializer(serializers.ModelSerializer):
	#有多张图片, many=True
    place_image = PlaceImageSerializer(many=True)

    class Meta:
        model = Place
        fields = "__all__"      
       

class PlaceViewSet(ModelViewSet):
    serializer_class = PlaceSerializer

    def list(self, request, **kwargs):
        queryset = Place.objects.prefetch_related('place_image')
        serializer = PlaceSerializer(queryset, many=True)
        response = {'code': 0, 'data': serializer.data, 'msg': '', 'total': len(serializer.data)}
        return Response(response)
        

• place
  
• place_image
  

{
    "code": 0,
    "data": [
        {
            "id": "1",
            "place_image": [
                {
                    "id": "1",
                    "name": "pic1"
                },
                {
                    "id": "2",
                    "name": "pic2"
                }
            ],
            "name": "School"
        },
        {
            "id": "2",
            "place_image": [
                {
                    "id": "3",
                    "name": "pic3"
                }
            ],
            "name": "Market"
        }
    ],
    "msg": "",
    "total": 2
}