views_基础方法

class MyView(View):

    def get(self, requests):
        """
        查询集：

        # 查询姐相当于列表，支持正值切片，索引，for等等
        # 查询集对数据库进行优化，会缓存结果
        # 惰性查询
        # 链式调用，性能优化

        """

        # one_obj = Projects.objects.create(name='项目1', leader='李白', desc='nb项目')
        # one_obj = Projects.objects.create(name='项目4', leader='王维', desc='nb项目4')
        # one_data = Projects.objects.get(id=2)
        # one_data = Projects.objects.all()

        """filter：查询集"""
        # one_qs = Projects.objects.filter(leader='李白')
        # one_qs = Projects.objects.exclude(id=2)
        # one_qs = Projects.objects.filter(id__gt=2)
        # one_qs = Projects.objects.filter(id__gte=2)
        # one_qs = Projects.objects.filter(id__in=[1, 3])
        # one_qs = Projects.objects.filter(leader__startswith='杜')
        # one_qs = Projects.objects.filter(leader__istartswith='杜')
        # one_qs = Projects.objects.filter(name__contains='2')
        # i: 忽略大小写
        # one_qs = Projects.objects.filter(name__icontains='2')
        # one_qs = Projects.objects.filter(id__gte=2)
        # one_qs = Projects.objects.filter(id__in=[1, 3])

        """
        多个条件（与的关系）：filter(desc__contains='nb', leader__startswith='李')
        链式查询：与上方查询结果一致 filter(desc__contains='nb').filter(leader__startswith='李')
        
        Q: 或 one_qs = Projects.objects.filter(Q(name__contains=1) | Q(leader__startswith='白'))
        Q: 与 one_qs = Projects.objects.filter(Q(name__contains=1) & Q(leader__startswith='白'))
        """
        # one_qs = Projects.objects.filter(desc__contains='nb', leader__startswith='李')
        # one_qs = Projects.objects.filter(desc__contains='nb').filter(leader__startswith='李')
        # one_qs = Projects.objects.filter(desc__contains='nb').exclude(leader__startswith='白')
        # one_qs = Projects.objects.filter(Q(name__contains=1) | Q(leader__startswith='白'))
        # one_list = []
        # for i in one_qs:
        #     one_dic = {
        #         'name': i.name,
        #         'leader': i.leader,
        #         'desc': i.desc,
        #     }
        #     one_list.append(one_dic)

        """
        关联查询：
        
        用子表信息查询父表数据：one_qs = Projects.objects.filter(interfaces__tester='测试3')
        用父表信息查询子表数据：one_qs = InterFaces.objects.filter(project__name__contains=2)
        """
        # one_qs = InterFaces.objects.filter(project__leader__contains='李')
        # one_qs = InterFaces.objects.filter(project__name__contains='项目')
        # one_qs = Projects.objects.filter(interfaces__name='接口2')
        # one_qs = Projects.objects.filter(interfaces__tester__startswith='测试')
        # print(one_qs.count())
        # print(len(one_qs))
        # print(one_qs.first())
        # print(one_qs.last())
        # print(one_qs.exists())
        # one_list = []
        # for i in one_qs:
        #     one_dic = {
        #         'id': i.id,
        #         'name': i.name,
        #         # 'leader': leader,
        #         'tester': i.tester,
        #         # 'desc': i.desc,
        #     }
        #     one_list.append(one_dic)
        #
        # return JsonResponse(one_list, safe=False)
        # return JsonResponse('', safe=False)

        # one_qs = Projects.objects.get(pk=1)
        # one_qs.leader = '苏轼'
        # one_qs.save()
        # one_dic = {
        #     'id': one_qs.id,
        #     'name': one_qs.name,
        #     'leader': one_qs.leader,
        # }

        # one_qs = Projects.objects.filter()
        # print(one_qs.values())
        # < QuerySet[{'id': 1, 'name': '项目1', 'leader': '苏轼', 'desc': 'nb项目1',
        #             'create_time': datetime.datetime(2020, 12, 27, 13, 28, 20, 801110,tzinfo= < UTC >), 'update_time':
        # datetime.datetime(2020, 12, 29, 15, 19, 7, 391951,tzinfo= < UTC >)}, {'id': 2,......

        # print(one_qs.values_list())
        # [(1, '项目1', '苏轼', 'nb项目1', datetime.datetime(2020, 12, 27, 13, 28, 20, 801110, tzinfo= < UTC >),
        #  datetime.datetime(2020, 12, 29, 15, 19, 7, 391951, tzinfo= < UTC >)),......

        # print(one_qs.values_list('id').order_by('id'))
        # < QuerySet[(1,), (2,), (3,), (4,)] >

        # print(one_qs.values_list('id', flat=True).order_by('id'))
        # < QuerySet[1, 2, 3, 4] >

        """
        raw: 
        可执行原生sql语句，性能更优
        """
        # one_qs = Projects.objects.raw('select name, leader from tb_project ')
        # print(one_qs)

        # one_qs = Projects.objects.aggregate(Count('id'))
        # print(type(one_qs), one_qs)

        # return JsonResponse(one_dic)
        return JsonResponse('', safe=False)