$ python manage.py makemigrations

$ python manage.py migrate

from django.db import models

from django.contrib.contenttypes.models import ContentType

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation

class DegreeCourse(models.Model):

    """学位课程"""

    name = models.CharField(max_length=128, unique=True)

    course_img = models.CharField(max_length=255, verbose_name="缩略图")

    brief = models.TextField(verbose_name="学位课程简介")

class Course(models.Model):

    """专题课程"""

    name = models.CharField(max_length=128, unique=True)

    course_img = models.CharField(max_length=255)

    # 不会在数据库生成列，只用于帮助你进行添加和查询

    policy_list = GenericRelation('PricePolicy')

class PricePolicy(models.Model):

    """价格与课程有效期表"""

    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)  # 关联course or degree_course

    object_id = models.PositiveIntegerField()

    # 不会在数据库生成列，只用于帮助你进行添加和查询

    content_obj = GenericForeignKey('content_type','object_id')

    valid_period_choices = (

        (1, '1天'),

        (3, '3天'),

        (7, '1周'),

        (14, '2周'),

        (30, '1个月'),

        (60, '2个月'),

        (90, '3个月'),

        (180, '6个月'),

        (360, '12个月'),

        (540, '18个月'),

        (720, '24个月'),

    )

    valid_period = models.SmallIntegerField(choices=valid_period_choices)

    price = models.FloatField()

from django.shortcuts import render, HttpResponse

from django.contrib.contenttypes.models import ContentType

from app01 import models

def test(request):

    """价格策略表中增加，查询"""

    # 1.在价格策略表中添加一条数据

    # 方法1

    """

    models.PricePolicy.objects.create(

        valid_period=7,

        price=6.6,

        content_type=ContentType.objects.get(model='course'),

        object_id=1

    )

    """

    # 方法2

    """

    models.PricePolicy.objects.create(

        valid_period=14,

        price=9.9,

        content_obj=models.Course.objects.get(id=1)

    )

    """

    # 2.根据某个价格策略对象，找到他对应的表和数据，如：管理课程名称

    '''

    price = models.PricePolicy.objects.get(id=2)

    print(price.content_obj.name)  # 自动帮你找到

    '''

    # 3、找到某个课程的所有价格策略

    obj = models.Course.objects.get(id=1)

    print(obj.policy_list.all())

    for item in obj.policy_list.all():

        print(item.id, item.valid_period, item.price)

    return HttpResponse('test...')