zoukankan      html  css  js  c++  java
  • django之content_type

    什么是content type:django内置的一个组件,这个组件帮忙做连表的操作。(混搭连表)

    适用场景:适用于一张表与多张表同时做关联的时候。直接导入就可以使用了。

    关联数据库说有的表;让我们可以快速插入数据,并且用反向查找能快速查找到数据。

    models.py文件建立表

    from django.db import models
    
    # Create your models here.
    from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation
    from django.contrib.contenttypes.models import ContentType
    
    class Course(models.Model):
        '''
        普通课程
        '''
        title=models.CharField(max_length=32)
        # 紧用于反向查找
        price_policy_list=GenericRelation('PricePolicy')
    
    class DegreeCourse(models.Model):
        '''
        学位课程
        '''
        title=models.CharField(max_length=32)
        # 仅用于反向查找
        price_policy_list=GenericRelation('PricePolicy')
    
    class PricePolicy(models.Model):
        '''
        价钱策略
        '''
        price = models.IntegerField()
        period = models.IntegerField()
    
        content_type=models.ForeignKey(ContentType,verbose_name='关联的表名称')
        object_id=models.IntegerField(verbose_name='关联的表中的数据行的ID')
    
        content_object=GenericForeignKey('content_type','object_id')
    
    # 1. 为学位课“Python全栈”添加一个价格策略:一个月 9.9
    """
    obj = DegreeCourse.objects.filter(title='Python全栈').first()
    # obj.id
    cobj = ContentType.objects.filter(model='course').first()
    # cobj.id
    PricePolicy.objects.create(price='9.9',period='30',content_type_id=cobj.id,object_id=obj.id)
    """
    

      views.py文件,进行数据插入和查看

    from django.shortcuts import render,HttpResponse
    
    # Create your views here.
    from app01 import models
    
    def test(request):
        # 1 为学位课python添加一个价格策略:一个月9.9
        # obj1=models.DegreeCourse.objects.filter(title='python').first()
        # models.PricePolicy.objects.create(price=9.9,period=30,content_object=obj1)
        #
        # obj1 = models.DegreeCourse.objects.filter(title='python').first()
        # models.PricePolicy.objects.create(price=19.9, period=60, content_object=obj2)
        #
        # obj1 = models.DegreeCourse.objects.filter(title='python').first()
        # models.PricePolicy.objects.create(price=29.9, period=90, content_object=obj3)
    
        # # 2 为学位课rest framework添加一个价格策略:一个月9.9
        # obj1=models.Course.objects.filter(title='rest framework').first()
        # models.PricePolicy.objects.create(price=9.9,period=30,content_object=obj1)
        #
        # obj2 = models.Course.objects.filter(title='rest framework').first()
        # models.PricePolicy.objects.create(price=19.9, period=60, content_object=obj2)
        #
        # obj3 = models.Course.objects.filter(title='rest framework').first()
        # models.PricePolicy.objects.create(price=29.9, period=90, content_object=obj3)
    
        # 3 根据课程的ID获取课程,并获取该课程的所有价格策略
        course=models.Course.objects.filter(id=1).first()
        price_policys=course.price_policy_list.all()
        print(price_policys)
        return HttpResponse('ok')
    
  • 相关阅读:
    UVALive 6909 Kevin's Problem 数学排列组合
    UVALive 6908 Electric Bike dp
    UVALive 6907 Body Building tarjan
    UVALive 6906 Cluster Analysis 并查集
    八月微博
    hdu 5784 How Many Triangles 计算几何,平面有多少个锐角三角形
    hdu 5792 World is Exploding 树状数组
    hdu 5791 Two dp
    hdu 5787 K-wolf Number 数位dp
    hdu 5783 Divide the Sequence 贪心
  • 原文地址:https://www.cnblogs.com/fangjie0410/p/8534614.html
Copyright © 2011-2022 走看看