Django没有显示来自数据库的更新数据

Posted 2023-02-24

【中文标题】Django没有显示来自数据库的更新数据

【英文标题】：Django not showing updated data from database

【发布时间】：2018-02-08 14:45:21

【问题描述】：

我有一个 django 1.11.4 应用程序在 windows 上的 mysql 5.6.16 上运行。当我添加新数据或更新现有数据时，直到我重新启动后才会显示新信息。我已经尝试按照here 的建议提供 db_name，但它并没有解决我的问题。

我还能如何解决这个问题？ 我正在使用 django 附带的默认 Web 服务器。 我的完整模型如下图

class Member(AbstractUser):

    first_name = models.CharField(verbose_name=_('First Name'), blank=False, max_length=100)
    last_name = models.CharField(verbose_name=_('Last Name'), blank=False, max_length=100)
    member_number = models.IntegerField(blank=False, unique=True)
    national_id = models.IntegerField(verbose_name=_('National ID Number'), blank=False, unique=True)
    phone_number = models.CharField(max_length=50, verbose_name=_('Phone Number'))
    email = models.EmailField(verbose_name=_('Email'), unique=True, max_length=100, blank=False)
    username = models.CharField(verbose_name=_('User name'), max_length=50, blank=True, null=True)
    position = models.CharField(verbose_name=_('Position in Society'),
                            max_length=100,
                            choices=(
                                ('MEMBER', 'Member'), ('COMMITTEE', 'Committee'), ('STAFF', 'Staff'),
                            ))
    employer = models.CharField(verbose_name=_('Employer'), max_length=250, blank=True)

    objects = UserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['member_number', 'national_id', 'first_name', 'last_name']

    class Meta:
        verbose_name = _('member')
        verbose_name_plural = _('members')
        db_table = 'members_member'

    def get_short_name(self):
        return self.last_name

    def __str__(self):
        return self.get_full_name()

我的数据库连接设置如下所示

DATABASES = 
    'default': 
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'open_db',
        'USER': 'root',
        'PASSWORD': 'rootpass',
        'HOST': 'localhost',
        'PORT': '3306',
    

这是创建成员的 views.py 类

class CreateMember(LoginRequiredMixin, PermissionRequiredMixin, CreateView):

    model = Member
    form_class = MemberCreationForm
    permission_required = ('members.add_member',)
    permission_denied_message = "Permission denied"

    def get(self, request, *args, **kwargs):

        return render(request, 'members/create_member.html', 'form': self.form_class)

    def post(self, request, *args, **kwargs):

        form = MemberCreationForm(data=request.POST,)

        if form.is_valid():

            form.save()

            messages.success(self.request, 'Success, member was added.', extra_tags='alert alert-success')

            return redirect(to='/members/directory')

        else:

            messages.error(self.request, 'Errors occurred.', extra_tags='alert alert-danger')

            return render(request, 'members/create_member.html', 'form': form)

然后是上面视图中使用的forms.py中使用的表单

    class MemberCreationForm(UserCreationForm):
        def __init__(self, *args, **kwargs):
            super(MemberCreationForm, self).__init__(*args, **kwargs)

            self.fields['email'].widget.attrs['class'] = 'form-control'
            self.fields['first_name'].widget.attrs['class'] = 'form-control'
            self.fields['last_name'].widget.attrs['class'] = 'form-control'
            self.fields['national_id'].widget.attrs['class'] = 'form-control'
            self.fields['member_number'].widget.attrs['class'] = 'form-control'
            self.fields['phone_number'].widget.attrs['class'] = 'form-control'
            self.fields['password1'].widget.attrs['class'] = 'form-control'
            self.fields['password2'].widget.attrs['class'] = 'form-control'
            self.fields['email'].widget.attrs.pop("autofocus", None)

        class Meta(UserCreationForm.Meta):
            model = Member
            fields = ('email', 'first_name', 'last_name', 'national_id', 'member_number', 'phone_number',)

然后是添加新成员后我重定向到的views.py中的ListView。

class MemberDirectory(LoginRequiredMixin, ListView, FormView):

    model = Member
    template_name = 'members/directory.html'
    paginate_by = 5

    try:
        context = 
            'total_members': Member.objects.all().count(),
            'active_members':     Member.objects.filter(is_active=True).count(),
            'staff_members': Member.objects.filter(is_staff=True).count(),
            'members_list': Member.objects.all().order_by('-date_joined')
    
    except Exception:
        context = 

    def get(self, request, *args, **kwargs):
        return render(request, self.template_name, self.context)

    def post(self, request, *args, **kwargs):

        member_number = int(self.request.POST['member_number'])

        if not member_number or not isinstance(member_number, int):
            messages.error(request, 'errors occured ...', 'alert alert-danger')
            return render(request, self.template_name, self.context)

        self.context['members_list'] =  Member.objects.filter(member_number__exact=member_number)
        return render(request, self.template_name, self.context)

最后是列出数据库中所有成员的 directory.html 模板。

% if members_list.count > 0 %
% include 'members/filters-form.html' %
<table class="table table-responsive table-striped">
<thead>
    <th>Name</th><th>Member number</th><th>Email</th><th>Phone</th><th>Actions</th>
</thead>
<tbody>
    % for member in members_list %

        <tr id="member-actions-tr">
            <td>
                <a title="% if member.is_active %Active member% else %Inactive member% endif %" href="% url 'members:member-details' pk=member.pk %">
                    <span class="glyphicon glyphicon-% if member.is_active %ok% else %alert% endif %" aria-hidden="true"></span>
                    &nbsp; member.get_full_name 
                </a>
            </td>
            <td> member.member_number </td>
            <td> member.email </td>
            <td> member.phone_number </td>
            <td>
                <div class="dropdown">
                  <button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                    Select <span class="caret"> </span>
                  </button>
                  <ul class="dropdown-menu dropdown-menu-right" aria-labelledby="dropdownMenu2" style="margin-top: 0px;">
                    <li><a href="% url 'payments:pay' member_id=member.pk %">Make payment</a></li>
                    <li><a href="#" class="" data-toggle="modal" data-target="#delete-member- member.pk "> Delete </a></li>
                  </ul>
                </div>
            </td>
        </tr>
    % endfor %
</tbody>
</table>

% else %
    <div class="panel panel-info"> No members were found. </div>
% endif %

【问题讨论】：

这似乎很不寻常。你能举个例子说明数据是如何不更新的吗？ minimal reproducible example

例如，如果我添加了一个新成员，然后转到所有成员列表，则新成员不会出现。当我通过 phpmyadmin 添加新成员时，也会发生同样的情况。新数据只有在我重新启动 django 服务器后才会显示。

我试过从mysql切换到sqlite3。同样的问题仍然存在。

这不是一个完整且可验证的示例。您应该添加一些用于尝试添加成员和检索列表的代码。数据库交互有很多步骤，我们无法从模糊的描述中知道会发生什么。

@HåkenLid 感谢您一直以来的支持。我刚刚添加了更多我正在使用的代码。请让我知道它是否足够。谢谢。

【参考方案1】：

这真的很容易。答案在文档here 和here 中。

因此，如下所示更改 MemberDirectory 列表视图确实有效！

class MemberDirectory(LoginRequiredMixin, ListView, FormView):

    model = Member
    template_name = 'members/directory.html'
    paginate_by = 5

    try:
        context = 
            'total_members': Member.objects.all().count(),
            'active_members':     Member.objects.filter(is_active=True).count(),
            'staff_members': Member.objects.filter(is_staff=True).count(),
        
    except Exception:
        context = 

    def get(self, request, *args, **kwargs):
        self.context['members_list'] = Member.objects.all().order_by('-date_joined')
        return render(request, self.template_name, self.context)

    def post(self, request, *args, **kwargs):

        member_number = int(self.request.POST['member_number'])

        if not member_number or not isinstance(member_number, int):
            messages.error(request, 'errors occured ...', 'alert alert-danger')
            return render(request, self.template_name, self.context)

        self.context['members_list'] = Member.objects.filter(member_number__exact=member_number)
        return render(request, self.template_name, self.context)

简单地说，之前的列表视图使用了一个查询集，该查询集包含对数据库进行更改之前的缓存数据。

【讨论】：

而你遇到麻烦的主要原因是因为你使用了所有这些mixin，然后自己做。如果使用普通的get_context_data 方法，您就不会出现这种情况。

@Melvyn 您将如何使用get_context_data 以及get 和post 方法重写MemberDirectory 类？