django contenttype

下图即为django的contenttype表

models.py

from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation


class PythonBasic(models.Model):
    course_name = models.CharField(max_length=32)
    coupon = GenericRelation("Coupon")   #  反向查询 通过此字段，类似于 releted_name
class Oop(models.Model):
    course_name = models.CharField(max_length=32)
    coupon = GenericRelation("Coupon")
class Coupon(models.Model):
    coupon_name = models.CharField(max_length=32)
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE) # 与django contenttype表建立外键

    object_id = models.PositiveIntegerField()  # 对应表中的对象id

    content_object = GenericForeignKey('content_type','object_id') # 不会生成列 

如何查询:

def get(self, request):

    pb = ContentType.objects.filter(app_label="auth",model='user').first() # 与contenttype表字段对应
    pb_model = pb.model_class() # 执行此方法拿到 <class 'django.db.models.base.ModelBase'>
    print(pb_model.objects.all())

如何创建：

object_id = PythonBasic.objects.get(pk=1)
Coupon.objects.create(coupon_name="python优惠卷",content_object = object_id)