Django一对一 ,一对多,多对多

向右看齐 2022-11-29 05:45 143阅读 0赞

### Django 数据库一对多,多对多 ###

*  目录
 *   *  app01/models.py
     *  app01/views.py
     *  app01/urls.py
     *  Python\_Django/urls.py

# 目录 #

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## app01/models.py ##

from django.db import models
    
    
    # Create your models here.
    # 1.继承 models.Model
    # 卖家
    class Seller(models.Model):
        id = models.AutoField(primary_key=True)  # 主键自动增长
        username = models.CharField(max_length=32)  # 字符串
        age = models.IntegerField()  # 年龄
        gender = models.BooleanField(default=True)  # 默认值是True 代表男
        phone = models.CharField(max_length=32)  # 电话
        email = models.EmailField()  # 邮箱类型
        # headimg = models.ImageField(default='1.jpg') # 图片类型 需要下载pillow 模块配合使用。
        headimg = models.CharField(max_length=128, default='1.jpg')  # 保存图片路径
        address = models.CharField(max_length=128)  # 地址
    
    
    # 店铺
    class Store(models.Model):
        # id 默认会自动添加
        name = models.CharField(max_length=32)  # 店铺名称
        address = models.CharField(max_length=128)  # 地址
        desc = models.CharField(max_length=128)  # 描述
        logo = models.CharField(max_length=128, default='1.jpg')  # logo
        # 店铺和卖家是一对一关系
        # to：属性是关联的表格名称，on_delete属性是删除策略，级联删除
        seller = models.OneToOneField(to='Seller', on_delete=models.CASCADE)
    
    
    # 商品类型
    class GoodsType(models.Model):
        name = models.CharField(max_length=32)  # 类型名称
        logo = models.CharField(max_length=128, default='1.jpg')  # 商品图片，用于前台显示
    
    # 商品
    class Goods(models.Model):
        name = models.CharField(max_length=32)  # 名称
        price = models.DecimalField(max_digits=5, decimal_places=2)
        # 价格 max_digits=5 总共5位，decimal_places=2 小数2位
        bzq = models.IntegerField()  # 保质期
        sczq = models.DateField(null=True, blank=True)  # 生产日期 null=True, blank=True 空
        image = models.CharField(max_length=128, default='1.jpg')  # 商品图片
        desc = models.TextField()  # 商品描述
        # 设置外键 关系
        # 商品和类型之间的关系
        goodstype = models.ForeignKey(to=GoodsType, on_delete=models.CASCADE)
        # 商品和店铺的关系
        store = models.ForeignKey(to=Store, on_delete=models.CASCADE, null=True, blank=True)
    
    
    # 多对多
    # 老师和学生多对多
    class Student(models.Model):
        name = models.CharField(max_length=32)
    
    
    class Teacher(models.Model):
        name = models.CharField(max_length=32)
        # 设置关系
        students = models.ManyToManyField(to=Student)

## app01/views.py ##

from django.db.models import Q, F, Count
    from django.http import HttpResponse
    from django.shortcuts import render
    
    # Create your views here.
    from app01 import models
    
    
    def register(request):
        if request.method == 'POST':
            # 1.获取表单提交的内容
            name = request.POST.get('name')
            password = request.POST.get('password')
            gender = request.POST.get('gender')
            phone = request.POST.get('phone')
            email = request.POST.get('email')
            address = request.POST.get('address')
            # 2.保存到数据库
            # 第一种方式
            # seller_obj = models.Seller()
            # seller_obj.username = name
            # seller_obj.password = password
            # seller_obj.phone = phone
            # seller_obj.address = address
            # seller_obj.gender = gender
            # seller_obj.email = email
            # seller_obj.save()
            # 第二种方式：
            models.Seller.objects.create(username=name,
                                         password=password,
                                         phone=phone,
                                         address=address,
                                         gender=gender,
                                         email=email)
            # 3.返回
            return HttpResponse('注册成功了...')
    
        return render(request, 'register.html')
    
    
    # 删除操作
    def delete_person(request):
        models.Seller.objects.get(id=1).delete()
        return HttpResponse('删除成功了...')
    
    
    # 更新操作
    def update_person(request):
        # 第一种方式：使用 save()
        # seller_obj = models.Seller.objects.get(id=2)
        # seller_obj.username = 'zhangsan'
        # seller_obj.password = '222'
        # seller_obj.save()
        # 第二种方式：使用update()
        ret = models.Seller.objects.filter(id=2).update(username='zs')
        # print(ret, type(ret)) # <class 'django.db.models.query.QuerySet'>
        return HttpResponse('修改成功了...')
    
    
    def findall(request):
        ret=models.Seller.objects.all()
        print(ret)
        return HttpResponse("查询所有数据........")
    def find(request):
        # 1. get() 直接返回当前对象, 只能返回一个对象，一般使用唯一标识
        ret = models.Seller.objects.get(id=2)
        # print(ret)
        # 2. filter(), 过滤，返回一个QuerySet类型的对象。当成列表使用即可
        # ret = models.Seller.objects.filter(password='222')
        # print(ret) # <QuerySet [<Seller: Seller object (2)>]>
        # print(ret[1].username)
    
        return HttpResponse('查询成功了...')
    # 条件查询
    def Filtle(req):
        # 排序 class类名.objects.order_by('字段名') (-字段名)表示降序
        print(models.Seller.objects.order_by("-id").all()) #<QuerySet [<Seller: Seller object (3)>, <Seller: Seller object (2)>]>
        #获取第一条数据 class类名.objects.first()
        print(models.Seller.objects.first()) #Seller object (2)
        # 获取最后一条数据 class类名.objects.last()
        print(models.Seller.objects.last())  # Seller object (3)
        #双下划线 字段__gte 大于等于 字段__gt 大于 字段__lt 小于 字段__lte 小于等于 字段__startswith 以什么开头
        print(models.Seller.objects.filter(id__gte=1).all()) #<QuerySet [<Seller: Seller object (2)>, <Seller: Seller object (3)>]>
    
        #聚合函数:aggregate
        #平均值 aggregate(Avg('字段'))
        #数目 aggregate(Count('字段'))
    
        #F和Q查询
        #性别是男而且电话是123的消费者
        print(models.Seller.objects.filter(gender=True,phone='123').all()) #<QuerySet [<Seller: Seller object (3)>]>
        #电话是123或者用户名是123的消费者
        print(models.Seller.objects.filter(Q(username=True) | Q(phone='123')).all()) #<QuerySet [<Seller: Seller object (3)>]>
    
        #F使用:同一张表格的不同字段进行比较
        print(models.Seller.objects.filter(username__lt=F('phone')).first())#None
        #分组查询
        #查询不同性别的人数
        print(models.Seller.objects.all().values('gender').annotate(Count('gender'))) #<QuerySet [{'gender': True, 'gender__count': 2}]>
        return HttpResponse("条件.........")
    
    # 一对一
    def onetoone(request):
        # 1.添加关系
        # 创建卖家
        seller_obj = models.Seller()
        seller_obj.username = 'wangwu'
        seller_obj.age = 18
        seller_obj.email = '110@qq.com'
        seller_obj.gender = True
        seller_obj.phone = '110'
        seller_obj.address = '南沙'
        seller_obj.save()
        # 创建店铺
        store_obj = models.Store()
        store_obj.name = '湛江烧烤'
        store_obj.address = '湛江'
        store_obj.desc = '天下第一烧烤'
        store_obj.seller = seller_obj  # 直接赋值对象，进行关系关联
        store_obj.save()
    
        return HttpResponse('okaaa')
    
    
    # 查询
    def onetoone2(request):
        # 正向查询
        # 查询 湛江烧烤对应的卖家
        store_obj = models.Store.objects.filter(name='湛江烧烤').first()
        # print(store_obj)
        seller_obj = store_obj.seller
        print(seller_obj)  # Seller object (1)
        print(seller_obj.username) #wangwu
        # 反向
        # 查询wangwu 对应的店铺
        seller_obj = models.Seller.objects.filter(username='wangwu').first()
        store_obj = seller_obj.store  # 直接类名小写即可。
        print(store_obj)  # Store object (1)
    
        return HttpResponse('okaaa')
    
    
    def onetoone3(request):
        seller_obj = models.Seller.objects.filter(username='wangwu').first()
        seller_obj.delete()  # 级联删除对应的店铺
        return HttpResponse('okaaa')
    
    
    # 一对多
    def onotomany(request):
        # 创建商品类型类型
        goodstype_obj = models.GoodsType(name='海鲜类')
        goodstype_obj.save()
        # 创建商品
        goods_obj1 = models.Goods(name='小龙虾', price=12.11, bzq=20, desc='大一点的小龙虾', goodstype=goodstype_obj)
        goods_obj1.save()
        goods_obj2 = models.Goods(name='波士顿龙虾', price=113.11, bzq=30, desc='小了点的大龙虾', goodstype=goodstype_obj)
        goods_obj2.save()
    
        return HttpResponse('oookkk')
    
    
    # 查询
    def onotomany2(request):
        # 正向查询
        # 1.小龙虾商品类型
        goods_obj = models.Goods.objects.filter(name='小龙虾').first()
        print(goods_obj)
        goodstype_obj = goods_obj.goodstype  # 直接通过关系属性查到对应的商品类型对象
        print(goodstype_obj)
        # 反向查询
        # 2.查询海鲜类对应的所有的商品
        goodstype_obj = models.GoodsType.objects.filter(name='海鲜类').first()
        # 反向查询： 类名小写_set.条件
        print(goodstype_obj.goods_set.all())
    
        return HttpResponse('oookkk')
    
    
    # 多对多添加关系
    
    def manytomay(request):
        teacher_obj1 = models.Teacher(name='扣王')
        teacher_obj2 = models.Teacher(name='狗哥')
        student_obj1 = models.Student(name='zs')
        student_obj2 = models.Student(name='lsi')
        teacher_obj1.save()
        teacher_obj2.save()
        student_obj1.save()
        student_obj2.save()
        # 使用 对象.关系属性.add(对象1，对象2...)
        teacher_obj1.students.add(student_obj1, student_obj2)
        teacher_obj2.students.add(student_obj1, student_obj2)
    
        return HttpResponse('okkk...')
    
    
    def manytomay2(request):
        # 查询狗哥 教过的学生
        # 正向查询
        # teacher_obj = models.Teacher.objects.filter(name='狗哥').first()
        # print(teacher_obj.students.all())
        # 反向查询：
        # zs 被哪些老师教过
        student_obj = models.Student.objects.filter(name='zs').first()
        ret = student_obj.teacher_set.all()
        print(ret)
        return HttpResponse('okkk...')

## app01/urls.py ##

from django.urls import path
    from . import views
    
    
    urlpatterns = [
        path('register',views.register),
        path('delete_person',views.delete_person),
        path('update_person',views.update_person),
        path('findall',views.findall),
        path('find',views.find),
        path('Filtle',views.Filtle),
        path('one/',views.onetoone),
        path('one2/',views.onetoone2),
        path('one3/',views.onetoone3),
        path('many/',views.onotomany),
        path('many2/',views.onotomany2),
        path('many2/',views.onotomany2),
        path('many_many/',views.manytomay),
        path('many_many2/',views.manytomay2),
    ]

## Python\_Django/urls.py ##

from django.contrib import admin
    from django.urls import *
    from app01 import views
    urlpatterns = [
        path('admin/', admin.site.urls),
        path('',include('app01.urls')),
    ]

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