ContentType

　　一般我们有多张表同时外键关联同一张表的时候，可以考虑使用ContentType

models.py

1 from django.db import models 2 from django.contrib.contenttypes.models import ContentType # django自己生成的表，里面存储着每一个app和它下面的表关系 3 from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation 4  5  6 class PythonBasic(models.Model): 7     course_name = models.CharField(max_length=32) 8     coupons = GenericRelation(to='Coupon') ##相当于foreignkey 9 10 11 class Oop(models.Model):12     course_name = models.CharField(max_length=32)13     coupons = GenericRelation(to='Coupon') ##相当于foreignkey14 15 16 class Coupon(models.Model):17     coupon_name = models.CharField(max_length=32)18     content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE) ##19     object_id = models.PositiveIntegerField() ##20 21     content_object = GenericForeignKey("content_type", "object_id") ## 在表中不会真的生成这个字段，但是对应关系是靠它实现的

views.py

1 class ContentTypeView(View): 2  3     def get(self, request): 4         # 获取表名 5         # pb = ContentType.objects.filter(app_label='app01', model='pythonbasic').first() 6         # print(pb.model_class()) # 
     
       7         # print(pb.model_class().objects.all()) # 
      
       , 
       
        , 
        
         ]> 8  9         # obj = PythonBasic.objects.get(id=3)10         obj = Oop.objects.get(id=2)11         # Coupon.objects.create(coupon_name="Python基础通关", content_object=obj)12         print(obj.coupons.all())13 14         return HttpResponse('ok')