Python django.db.utils.IntegrityError:唯一约束失败：模式\设置。用户\ id

我是Javascript新手，目前正在学习调试控制台中接收到的错误

在我的项目中，我为每个登录网站的用户添加了一个主题选择选项。当前，当我单击按钮时，它显示了2个主题，但它没有为每个用户保存主题

我已经在Django项目中创建了一个应用程序，除了在控制台中每次从按钮中选择主题时都会收到错误外，所有内容都与我下面的教程中介绍的内容相同：

(index):573 POST http://127.0.0.1:8000/update_theme/ 500 (Internal Server Error)

并且在终端中出现此错误：

    <link id="mystylesheet" href="{% static 'css/app-light.css' %}" type="text/css" rel="stylesheet">
        <!-- Mode -->
        <div id="mode" class="section" style="padding-top: 1rem; padding-bottom: 3rem;text-align: right">
            <button onclick="swapStyles('app-light.css')" type="button" class="btn btn-secondary">Light Mode</button>
            <button onclick="swapStyles('app-dark.css')" type="button" class="btn btn-dark">Dark Mode</button>
        </div>
        <!-- Mode -->

django.db.utils.IntegrityError:唯一约束失败：模式设置。用户id

这是基本模板：

    <link id="mystylesheet" href="{% static 'css/app-light.css' %}" type="text/css" rel="stylesheet">
        <!-- Mode -->
        <div id="mode" class="section" style="padding-top: 1rem; padding-bottom: 3rem;text-align: right">
            <button onclick="swapStyles('app-light.css')" type="button" class="btn btn-secondary">Light Mode</button>
            <button onclick="swapStyles('app-dark.css')" type="button" class="btn btn-dark">Dark Mode</button>
        </div>
        <!-- Mode -->

这是视图。py

def userSettings(request):
    user = request.user
    setting = getattr(user, 'setting', None)

    if setting:
        seralizer = UserSerailizer(setting, many=False)
        return JsonResponse(seralizer.data, safe=False)
    else:
        return JsonResponse({'message': "User don't have a setting."}, safe=False)


def updateTheme(request):
    data = json.loads(request.body)
    theme = data['theme']

    user=request.user
    setting = Setting.objects.get_or_create(user=user, value=theme, name=user.username)
    setting.save()
    print('Request:', theme)
    return JsonResponse('Updated..', safe=False)

app_name = 'mode'


urlpatterns = [
    path('user_settings/', views.userSettings, name="user_settings"),
    path('update_theme/', views.updateTheme, name="update_theme"),
]

from .models import *

class UserSerailizer(serializers.ModelSerializer):
    class Meta:
        model = Setting
        fields = '__all__'

url.py

def userSettings(request):
    user = request.user
    setting = getattr(user, 'setting', None)

    if setting:
        seralizer = UserSerailizer(setting, many=False)
        return JsonResponse(seralizer.data, safe=False)
    else:
        return JsonResponse({'message': "User don't have a setting."}, safe=False)


def updateTheme(request):
    data = json.loads(request.body)
    theme = data['theme']

    user=request.user
    setting = Setting.objects.get_or_create(user=user, value=theme, name=user.username)
    setting.save()
    print('Request:', theme)
    return JsonResponse('Updated..', safe=False)

app_name = 'mode'


urlpatterns = [
    path('user_settings/', views.userSettings, name="user_settings"),
    path('update_theme/', views.updateTheme, name="update_theme"),
]

from .models import *

class UserSerailizer(serializers.ModelSerializer):
    class Meta:
        model = Setting
        fields = '__all__'

序列化程序.py

def userSettings(request):
    user = request.user
    setting = getattr(user, 'setting', None)

    if setting:
        seralizer = UserSerailizer(setting, many=False)
        return JsonResponse(seralizer.data, safe=False)
    else:
        return JsonResponse({'message': "User don't have a setting."}, safe=False)


def updateTheme(request):
    data = json.loads(request.body)
    theme = data['theme']

    user=request.user
    setting = Setting.objects.get_or_create(user=user, value=theme, name=user.username)
    setting.save()
    print('Request:', theme)
    return JsonResponse('Updated..', safe=False)

app_name = 'mode'


urlpatterns = [
    path('user_settings/', views.userSettings, name="user_settings"),
    path('update_theme/', views.updateTheme, name="update_theme"),
]

from .models import *

class UserSerailizer(serializers.ModelSerializer):
    class Meta:
        model = Setting
        fields = '__all__'

我的问题我收到此错误的原因以及如何修复它？

您使用的是错误的，因为您按所有字段进行筛选，并且在数据库中找不到已存在的实例，这将导致get\u或\u create尝试创建另一个实例

因此，您应该将只需要更新为默认值的字段移动到文档中

setting = Setting.objects.get_or_create(user=user, defaults={'value': theme, 'name'= user.username)

---

另外

• 将

  user.username

  存储为字段是数据重复，这毫无意义
• 在

  get\u或\u create

  之后调用

  setting.save（）

  是不必要的，因为您可以使用

---

我遵循您的代码，主题保存在DB中，我同意您关于

update\u或\u create

的看法，但现在当我刷新页面时，它返回到light主题，尽管它保存为

app dark.css

在控制台中，我收到

数据：{消息：“用户没有设置。”}消息：“用户没有设置。”__proto__:Object

如果您有更多问题要问新问题，则这似乎与问题中描述的问题无关