contentType

ContentType组件
    解决什么问题：表的id和数据id，来唯一确定一条数据
    用：
        插入数据：
             models.PricePolicy：content_obj = GenericForeignKey('table_id', 'course_id')
             views：
                    course=models.Course.objects.filter(pk=1).first()
                    models.PricePolicy.objects.create(period=9,price=100,content_obj=course)
        
        查询数据：
            1 查询所有价格策略，并且显示对应的课程名称:
               models.PricePolicy：
                        from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation
                        content_obj = GenericForeignKey('table_id', 'course_id')
               views:
                        # ret=models.PricePolicy.objects.all()
                        # for price in ret:
                        #     print(type(price.content_obj))
                        #     print(price.content_obj.title)   
            2 通过课程id，获取课程信息和价格策略:
                modes.Course
                    from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation
                    policy = GenericRelation('PricePolicy',object_id_field='object_id',content_type_field='content_type')
                views:
                    # course = models.Course.objects.filter(pk=1).first()
                    # print(course.policy.all())
                    # for i in course.policy.all():
                    #     print(i.price)

from django.db import models

# Create your models here.

from django.contrib.contenttypes.models import ContentType

# 第二种方式
from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation

class Course(models.Model):
    title=models.CharField(max_length=32)
    # 三 不会在数据库中生成字段，只用于数据库操作
    policy = GenericRelation('PricePolicy',object_id_field='object_id',content_type_field='content_type')

class DegreeCourse(models.Model):
    title=models.CharField(max_length=32)
    # 三 不会在数据库中生成字段，只用于数据库操作
    policy = GenericRelation('PricePolicy', object_id_field='object_id', content_type_field='content_type')

class PricePolicy(models.Model):
    period=models.IntegerField()
    price=models.PositiveIntegerField()

    content_type=models.ForeignKey(to=ContentType,null=True)  #表名
    object_id=models.PositiveIntegerField(null=True) #课程id

    # 第二种方式
    # 引入一个字段，不会在数据库中创建，只用来做数据库操作
    content_obj = GenericForeignKey('content_type', 'object_id')

from django.shortcuts import render,HttpResponse

# Create your views here.
from app01 import models

def addPrice(request):

    '''
    为专题课，添加三个价格策略
    查询所有价格策略，并且显示对应的课程名称
    通过课程id，获取课程信息和价格策略
    '''
    # 为专题课django课程，添加三个价格策略
    # 1 普通方式
    # course=models.Course.objects.filter(pk=1).first()
    # content=models.ContentType.objects.filter(model='course').first()
    # models.PricePolicy.objects.create(period=1,price=0,object_id=course.pk,content_type_id=content.pk)
    # models.PricePolicy.objects.create(period=3,price=49,object_id=course.pk,content_type_id=content.pk)
    # models.PricePolicy.objects.create(period=6,price=69,object_id=course.pk,content_type_id=content.pk)

    # 2 GenericForeignKey
    # course=models.Course.objects.filter(pk=1).first()
    # models.PricePolicy.objects.create(period=9,price=100,content_obj=course)

    # 为Python全站开发学位课，加一个价格策略
    # degree = models.DegreeCourse.objects.filter(pk=1).first()
    # models.PricePolicy.objects.create(period=2,price=50,content_obj=degree)

    # 二 查询所有价格策略，并且显示对应的课程名称
    # ret=models.PricePolicy.objects.all()
    # for price in ret:
    #     print(type(price.content_obj))
    #     print(price.content_obj.title)

    #三 通过课程id，获取课程信息和价格策略
    # course = models.Course.objects.filter(pk=1).first()
    # print(course.policy.all())
    # for i in course.policy.all():
    #     print(i.price)
    # 查专题课程 python全站开发
    degree = models.DegreeCourse.objects.filter(pk=1).first()
    print(degree.policy.all())
    for i in degree.policy.all():
        print(i.price)

    return HttpResponse('ok')

"""day06 URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/1.11/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  url(r'^$', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  url(r'^$', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.conf.urls import url, include
    2. Add a URL to urlpatterns:  url(r'^blog/', include('blog.urls'))
"""
from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^test/', views.addPrice),
]