ORM单表操作的增删改查

增加记录

def add(request):

    # 添加记录的方法1
    # book1=Book(title="北京折叠",price="11.11",pub_date="2012-12-12",publish='苹果出版社')
    # book1.save()

    # 添加记录的方法2 create返回记录对象
    # book_obj=Book.objects.create(title="放风筝的人",price="11.11",pub_date="2017-12-12",publish='苹果出版社')
    # print(book_obj.title)
    # print(book_obj.price)
    # print(book_obj.pub_date)
   
    return HttpResponse("添加成功")

查询记录

def query(request):

    '''
    queryset:列表里存对象 调不了属性
    model对象

    :param request:
    :return:
    '''

    # 1. all()
    # book_list = Book.objects.all()  #queryset数据类型[obj,obj....]
    # print(book_list)
    # for obj in book_list:
    #     print(obj.title)

    # 2. filter() 返回的是一个queryset数据类型对象，【model_obj,model_obj】
    # ret=Book.objects.filter(title="北京折叠")
    # print(ret)

    # 3.first,last,queryset支持切片操作
    # obj1=Book.objects.all().first()
    # obj2=Book.objects.all().last()
    # # obj3=Book.objects.all()[1:2]
    # print(obj1)
    # print(obj2)
    # # obj4=Book.objects.all()[-1]

    # 4.get方法 返回的就是一个model对象,有且只有一个才有意义
    # obj =Book.objects.get(nid=1)
    # print(obj.title)

    # 5.exclude 排除 等同于filter
    # ret = Book.objects.exclude(nid=1)
    # print(ret)

    # 6.order_by排序
    # ret=Book.objects.order_by('price')
    # print(ret)

    # 7.reverse()反向排序
    # ret=Book.objects.order_by('price').reverse()

    # 8 count
    # ret=Book.objects.all().count()
    # print(ret)

    # 9 exists
    # ret=Book.objects.all().exists()
    # if ret:
    #     print('ok')

    # 10 返回query，列表里套字典，每本书都是字典
    # ret = Book.objects.all().values("title", "price")
    # print(ret)

    # 11 values_list 列表里套元祖
    # ret = Book.objects.all().values_list('title','price')
    # print(ret)

    # 12 distinct(去重）

    # 单表查询之模糊查询
    # Book.objects.filter(price__gt=100)
    # Book.objects.filter(price__lt=100)
    # ret=Book.objects.filter(price__lte=100)
    # print(ret)
    # Book.objects.filter(price__gte=100)

    # Book.objects.filter(price__in=[100,200,300])

    # Book.objects.filter(price_range=[100,233])

    # Book.objects.filter(title__startswith="北")

    # Book.objects.filter(title__contains="传")

    return HttpResponse("查询成功")

更改记录

def change(request):
    nid=1
    Book.objects.filter(nid=nid).update(price=1000)
    return HttpResponse('修改成功')

删除记录

def delbook(request,id):

    Book.objects.filter(nid=id).delete()

    return HttpResponse("删除成功")

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