b2 = BookInfo.objects.get(id=2) h.hbook = b2#给关系属性赋值,英雄对象所属的图书对象 h.save() 书表里面的所有内容。 BookInfo.objects.all() HeroInfo.objects.all() 6.5 关联操作 查询出id为2的图书中所有英雄人物的信息。 b = BookInfo.objects.get(id=2) b.heroinfo_set.all()#查询出b图书中...
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>>> from django.db.models import Exists, OuterRef >>> non_unique_account_type = Client.objects.filter( ... account_type=OuterRef('account_type'), ... ).exclude(pk=OuterRef('pk')).values('pk') >>> When(Exists(non_unique_account_type), then=Value('non unique')) >>> # Conditio...
if goods.exists(): return Response({"status": "已存在", "goods_category": data}, status=200) else: return Response({"status": "不存在", "goods_category": data}, status=404) ### APIView class GetGoods(APIView): def get(self, request): data = Goods.objects.all() serializer = Goo...
存储在缓存中,就只会执行便利的那一次引用的sql执行,在对orm语句进行操作时,就会从缓存中获取数据。效率提高 方式2:使用if语句也可以orm数据存储到缓存中 5.exists()与iterator()2 # exists()优化查询方案 # 查询某张表存在记录 每个数据类型都有一个0值 空 在布尔值中:bool("")为False,其他的都为...
importUser>>>User.objects.create(username='alice',pk=1)<User: alice>>># The sequence hasn't been updated; its next value is 1.>>>User.objects.create(username='bob')...IntegrityError: duplicate key value violates unique constraint"auth_user_pkey" DETAIL: Key (id)=(1) already exists. ...
username=self.cleaned_data.get('username')ifUser.objects.filter(username=username).exists():raise forms.ValidationError('用户名已存在!')returnusername defclean_mobile(self):"""校验手机号码:return:""" mobile=self.cleaned_data.get('mobile')ifUser.objects.filter(mobile=mobile).exists():raise forms...
""" 校验手机号 """ # 用户的输入 input_phone = self.cleaned_data["phone_num"] # 先去数据库查看是否已存在此手机号,已存在不能重复添加 is_exists = models.LightPhone.objects.filter(phone_num=input_phone).exists() if is_exists: raise ValidationError('手机号已存在,不允许重复添加') if len...
Django 不建议重复加载 Model 的定义.# 作为 demo 可以直接通过get_log_model获取,无视警告.# 所以这里先通过 all_models 获取已经注册的 Model,# 如果获取不到, 再生成新的模型.try:cls=apps.get_model('__main__','Log_%s'%today)except LookupError:cls=get_log_model(today)ifnot cls.is_exists():...
# Get corresponding Loguru level if it exists try: level = self._logger.level(record.levelname).name except ValueError: level = record.levelno # Find caller from where originated the logged message frame, depth = logging.currentframe(), 2 ...