django contenttype

from django.shortcuts import render, HttpResponsefrom app01 import modelsfrom django.contrib.contenttypes.models import ContentTypedeftest(request): if request.method == 'GET':

        # ContentType表对象有model_class() 方法，取到对应model        content = ContentType.objects.filter(app_label='app01', model='electrics').first()  # 表名小写        cloth_class = content.model_class() # cloth_class 就相当于models.Electrics        res = cloth_class.objects.all()

        print(res)

        # 为三星电视(id=2)创建一条优惠记录        s_tv = models.Electrics.objects.filter(id=2).first()

        models.Coupon.objects.create(name='电视优惠券', content_object=s_tv)

        # 查询优惠券（id=1）绑定了哪些商品        coupon_obj = models.Coupon.objects.filter(id=1).first()

        prod = coupon_obj.content_object

        print(prod)

        # 查询三星电视(id=2)的所有优惠券        res = s_tv.coupons.all()

        print(res)

        # 查询obj的所有优惠券：如果没有定义反向查询字段，通过如下方式：        content = ContentType.objects.filter(app_label='app01', model='model_name').first()

        res = models.OftenAskedQuestion.objects.filter(content_type=content, object_id=obj.pk).all()

        return HttpResponse('....')

from django.db import modelsfrom django.contrib.contenttypes.models import ContentTypefrom django.contrib.contenttypes.fields import GenericForeignKeyclassElectrics(models.Model): name = models.CharField(max_length=32)

    coupons = GenericRelation(to='Coupon')  # 用于反向查询，不会生成表字段    def__str__(self):        return self.nameclassFoods(models.Model):    name = models.CharField(max_length=32)

    coupons = GenericRelation(to='Coupon')

    def__str__(self):        return self.nameclassClothes(models.Model):    name = models.CharField(max_length=32)

    coupons = GenericRelation(to='Coupon')

    def__str__(self):        return self.nameclassCoupon(models.Model):    name = models.CharField(max_length=32)

    content_type = models.ForeignKey(to=ContentType) # step 1    object_id = models.PositiveIntegerField() # step 2    content_object = GenericForeignKey('content_type', 'object_id') # step 3    def__str__(self):        return self.name