"""

# Course表

# id         name

   1      Python入门        

# DegreeCourse表

# id         name

   1      Python全栈    

# PricePolicy表

# id         day         price        couse_id    course_type(外键)

   1        7            0                1            1

   2        14            9.9                1            1

   3        180            18888            1            2  

# ContentType表

id         table_name

1          course

2          degreecourse

"""

from django.db import models

from django.contrib.contenttypes.fields import GenericRelation

class Course(models.Model):

    name = models.CharField(max_length=32)

    # price_policy = GenericRelation(to='PricePolicy',object_id_field='object_id',content_type_field='content_type')

    # 当你的类GenericRelation关联的表PricePolicy中的字段和(object_id_field='object_id', content_type_field='content_type'),

    # 字段名字完全一致时可以省略object_id_field和content_type_field的参数

    price_policy = GenericRelation(to='PricePolicy')  # 用户连表查询，不会在数据库中产生字段

class DegreeCourse(models.Model):

    name = models.CharField(max_length=32)

    price_policy = GenericRelation(to='PricePolicy')

from django.contrib.contenttypes.models import ContentType

from django.contrib.contenttypes.fields import GenericForeignKey

class PricePolicy(models.Model):

    day = models.IntegerField()

    price = models.CharField(max_length=8)

    # course_id = models.IntegerField()  # 某课程表的主键，但是不具备唯一性，所以只能用IntegerField

    # course_type = models.CharField(max_length=16)  # 一会儿要改成外键

    # course_type = models.ForeignKey(to=ContentType, null=True)

    # model_object = GenericForeignKey(ct_field='course_type', fk_field='course_id')

    object_id = models.IntegerField()

    content_type = models.ForeignKey(to=ContentType, null=True)

    #   改操作只用于ContentType连表查询，不会产生表字段，就是关联课程表的对象

    # 当你在此类中有和GenericForeignKey所需要的参数(ct_field='content_type', fk_field='object_id'),

    # 即ct_field和fk_field参数所需的字段名字完全一致时可以胜率这两个参数的值

    model_object = GenericForeignKey()

from django.shortcuts import HttpResponse

from api import models

def add_course(request):

    # 为python入门 免费课增加两条价格策略

    # course = models.Course.objects.filter(pk=1).first()

    # content_type = models.ContentType.objects.filter(model='course').first()# course应该写活

    # models.PricePolicy.objects.create(day=7, price=0, course_id=course.pk, content_type=content_type)

    # course = models.Course.objects.filter(pk=1).first()

    # print(course._meta.model_name)  # 为model对象表名小写

    # content_type = models.ContentType.objects.filter(model=course._meta.model_name).first()

    # models.PricePolicy.objects.create(day=14, price=9.9, course_id=course.pk, content_type=content_type)

    # 上述方法是在models.py中PricePolicy类中的course_id和course_type字段没有注释之前的方法

    # 为Python全栈 学位课程添加一条价格策略  采用ContentType来实现

    # degree_course = models.DegreeCourse.objects.filter(pk=1).first()

    # models.PricePolicy.objects.create(day=180, price=18888, model_object=degree_course)

    # 查找所有课程的所有价格策略

    # price_policy_list = models.PricePolicy.objects.all()

    # for price_policy in price_policy_list:

    #     print(price_policy.model_object.name, price_policy.day, price_policy.price)

    # 查看Python入门的所有价格策略

    course = models.Course.objects.filter(pk=1).first()

    price_policy_list = course.price_policy.all()

    for price_policy in price_policy_list:

        print(course.name, price_policy.day, price_policy.price)

    return HttpResponse('ok')