我有两个具有多对多关系的模型，我试图通过从两个模型中减去两个值来更新字段并将更改保存到数据库。
class LeaveBalance(models.Model):
user=models.OneToOneField(User,on_delete=models.CASCADE,primary_key=True,)
Leave_current_balance= models.FloatField(null=True, blank=True, default=None)
Year=models.CharField(max_length=100,default='')
def __unicode__(self):
return self.Year
class NewLeave(models.Model):
user=models.ForeignKey(User,default='',on_delete=models.CASCADE)
leave_balance=models.ManyToManyField(Leave_Balance)
leave=(
('annual','annual'),
('sick','sick'),
)
Leave_type=models.CharField(max_length=100,choices=leave,blank=False,default='')
Total_working_days=models.FloatField(null=True, blank=False)
DirAuth=(
('Pending','Pending'),
('Approved','Approved'),
('Rejected','Rejected'),
)
Director_Authorization_Status=models.CharField(max_length=100,choices=DirAuth,default='Pending',blank=False)
Date_Authorized=models.DateField(null=True,blank=False)
Authorized_by_Director=models.CharField(max_length=100,default='',blank=False)
def __unicode__(self):
return self.Leave_type
这是我的表格，请假后，将通过电子邮件通知董事。主管可以使用该表格登录系统以批准休假。请假获得批准后，我要调整Leave_current_balance。
class DirectorForm(forms.ModelForm):
class Meta:
model=NewLeave
fields=('Director_Authorization_Status','Authorized_by_Director','Date_Authorized',)
widgets={
'Date_Authorized':DateInput()
}
此功能允许主管批准引发错误的休假：u'Leave_current_balance'
def unitDirectorForm(request,id):
if request.method=='POST':
getstaffid=NewLeave.objects.get(id=id)
form = DirectorForm(request.POST, instance=getstaffid)
if form.is_valid():
getstaffid = form.save(commit=False)
getstaffid.save()
total_days = getstaffid.Total_working_days
current_balance = getstaffid.user.leave_balance.Leave_current_balance
diff_balance = current_balance - total_days
current_balance = diff_balance
current_balance=form.fields['Leave_current_balance']
current_balance.save()
getstaffid.leave_balance.add(current_balance)
return HttpResponse('You have successfuly Authorise the leave')
else:
#getstaffid=NewLeave.objects.get(id=id)
form=DirectorForm()
#c_balance=Leave_Balance.objects.get()
balance_form = leavebbalanceForm()
return render(request,'managerauthorisedform.html',{'form':form})
答案 0 :(得分：0)
您必须在余额上致电refresh_from_db。像balance.refresh_from_db()一样从数据库中获取更新的值。
答案 1 :(得分：0)
您也可以通过其他方式使它工作。例如：
def on_balance(user_id):
id = user_id
c_balance = LeaveBalance.objects.get(user=id)
current_balance = c_balance.Leave_current_balance
t_days = NewLeave.objects.get(user=id)
total_days = t_days.Total_working_days
current_balance = current_balance - total_days
balance = LeaveBalance.objects.get(user=id)
balance.leave_balance = current_balance
balance.save()
并且上述情况不会导致组合表达式错误。
或者更简单一些：
def on_balance(user_id):
id = user_id
c_balance = LeaveBalance.objects.get(user=id)
current_balance = c_balance.Leave_current_balance
t_days = NewLeave.objects.get(user=id)
total_days = t_days.Total_working_days
current_balance = current_balance - total_days
c_balance.leave_balance = current_balance
c_balance.save()
更新-重构模型和视图
因此，如果在适当的模型/表单/视图结构中使用上述代码，则可以使用上述代码，但我建议您从模型开始重新构建整个代码。我给你一个简单的工作示例（我对此进行了测试并起作用）：
我的应用名称在此示例中：Myusers1，因此无论您在哪里看到，都可以根据需要将该名称更改为您的应用名称。
所以模型：
from django.db import models
from django.conf import settings
from django.utils.text import slugify
from django.db.models import F
from django.urls import reverse
class Director(models.Model):
name = models.CharField(max_length = 100, default = '', null = True, verbose_name = 'Name of Director')
def __str__(self):
return self.name
class Staff(models.Model):
TYPE_CHOICES = (
('REGULAR', 'Regular'),
('MANAGER', 'Manager'),
('FRESH', 'Fresh'),
)
name = models.CharField(max_length = 100, default = '', null = True, unique=True, verbose_name = 'Name of staff member')
birthdate = models.DateField(blank = True, verbose_name = 'Birth date')
department = models.CharField(max_length = 100, default = '', null = True, verbose_name = 'Department')
# department could also be a choice field from another table
type = models.CharField(max_length = 20, choices = TYPE_CHOICES, verbose_name = 'Position Type', null = True)
def __str__(self):
return self.name
class LeaveBalance(models.Model):
staff = models.ForeignKey(Staff, to_field='name', on_delete = models.CASCADE, primary_key = False)
Leave_current_balance = models.FloatField(null = True, blank = True, default = '')
date_updated = models.DateTimeField(auto_now_add = True, verbose_name = 'Last Updated date and time')
def __unicode__(self):
return self.Leave_current_balance
class NewLeave(models.Model):
all_staff = Staff.objects.values()
STAFF_CHOICES = [(d['name'], d['name']) for d in all_staff]
staff = models.CharField(max_length = 100, choices = STAFF_CHOICES)
leave_days_to_approve_now = models.FloatField(null = True, blank = False, default = 5.0, verbose_name = 'Leave days for approval now')
LEAVE_CHOICES=(
('annual','annual'),
('sick','sick'),
)
Leave_type = models.CharField(max_length = 100, choices = LEAVE_CHOICES, blank = False, default = '', verbose_name = 'Type of leave')
Total_working_days = models.FloatField(null = True, blank = False, default = 200.0)
APPROVAL_STATUS_CHOICES=(
('Pending','Pending'),
('Approved','Approved'),
('Rejected','Rejected'),
)
Director_Authorization_Status = models.CharField(max_length = 100, choices = APPROVAL_STATUS_CHOICES, default = 'Pending', blank = False)
Date_Authorized = models.DateTimeField(auto_now_add = True, verbose_name = 'date and time of Authorization')
all_directors = Director.objects.values()
DIRECTOR_CHOICES = [(d['name'], d['name']) for d in all_directors]
Authorized_by_Director = models.CharField(max_length = 100, choices = DIRECTOR_CHOICES, default = '', blank = False)
def __unicode__(self):
return self.Leave_type
def get_absolute_url(self):
pass
# return reverse('newleave-detail', kwargs={'pk': self.pk}) # this should be worked out too
def save(self, *args, **kwargs):
staff_name = self.staff
this_staff = Staff.objects.get(name=staff_name)
name = this_staff.name
minus_value = self.leave_days_to_approve_now
if (self.Director_Authorization_Status == 'Approved'):
LeaveBalance.objects.filter(staff = name).update(Leave_current_balance=F('Leave_current_balance') - minus_value)
return super(NewLeave, self).save(*args, **kwargs)
else:
return super(NewLeave, self).save(*args, **kwargs)
在上面的中，您可以看到我创建了一个 Director 和 Staff 模型，在其中可以设置与您想要在Admin后端中。我创建了人员模型，因为可能不是所有人员都将是用户，所以我认为最好将它们与用户分开保存在数据库中。
重要：首先创建Director和Staff模型，然后立即迁移，因为其他两个表将依赖它们。然后，您可以创建其他两个模型。
我也不认为在 LeaveBalance模型中，您应该保留的东西比我放置的要多。我认为“年份”字段是多余的，因为您始终可以按数据库中所需的日期和日期范围进行过滤。
然后是视图（我仅直接从模型中使用简单视图）。使用这些视图类时，您不必创建窗体，因为它是从模型自动创建的，并且可以在视图和模型类中使用不同的函数/方法（如窗体）来处理它们。
from django.shortcuts import render, redirect
from django.http import HttpResponseRedirect, HttpResponse, HttpRequest
from django.urls import reverse
from django.views import View
from django.views.generic.detail import DetailView
from django.views.generic import ListView, TemplateView
from django.template import loader
from .models import NewLeave
from django.views.generic.edit import FormView, CreateView, DeleteView, UpdateView
from django.urls import reverse_lazy
class NewLeaveCreate(CreateView):
model = NewLeave
fields = '__all__'
def form_valid(self, form):
super().form_valid(form)
auth_status = form.cleaned_data['Director_Authorization_Status']
if (auth_status == 'Approved'):
return redirect('Myusers1:success_page')
elif (auth_status == 'Pending'):
return redirect('Myusers1:pending_success')
else:
return redirect('Myusers1:rejected_success')
class NewLeaveUpdate(UpdateView):
model = NewLeave
fields = '__all__'
class NewLeaveDelete(DeleteView):
model = NewLeave
success_url = reverse_lazy('newleave-list')
class NewLeaveDetail(DetailView):
model = NewLeave
template_name = 'myusers1/newleave_detail.html'
context_object_name = 'newleave'
queryset = NewLeave.objects.all()
def get_context_data(self, **kwargs):
context = super(NewLeaveDetail, self).get_context_data(**kwargs)
context['leave_details'] = NewLeave.objects.filter(pk=pk)
return context
class Success(TemplateView):
template_name = "authorizationsuccess.html"
class pending_success(TemplateView):
template_name = "pendingsuccess.html"
class rejected_success(TemplateView):
template_name = "rejectedsuccess.html"
然后在urls.py中，我定义了所需的网址：
from django.urls import path, re_path
from . import views
from . import models
app_name = 'Myusers1'
urlpatterns = [
path('newleave/add/', views.NewLeaveCreate.as_view(), name='newleave-add'),
path('newleave/<int:pk>/', views.NewLeaveUpdate.as_view(), name='newleave-update'),
path('newleave/<int:pk>/delete/', views.NewLeaveDelete.as_view(), name='newleave-delete'),
# path('newleave/add/<int:pk>/', views.NewLeaveDetail.as_view(), name='newleave-detail'),
path('newleave/add/success/', views.Success.as_view(), name='success_page'),
path('newleave/add/pendingleaves/', views.pending_success.as_view(), name='pending_success'),
path('newleave/add/rejectedleaves/', views.rejected_success.as_view(), name='rejected_success'),
]
我还没有计算出所有的URL路径。
模板和newleave_form.html
{% extends 'myusers1/base.html' %}
{% block content %}
<div class"container">
<div class="col col-lg-2">
<h2>New Leave Form</h2>
<form method="post">
{% csrf_token %}
{{ form }}
<button type="submit">Authorize</button>
</form>
</div>
</div>
{% endblock %}
并且当他们提交一个NewLeave表单authorized, pending, and rejected模板时，至少应该有三个不同的重定向模板。我只在这里给出简单的授权成功模板：
{% extends 'myusers1/base.html' %}
{% block content %}
<h2>Thank you! The authorization of leave was successful</h2>
<div class="col-xs-12 .col-md-8"><li><a href="{% url 'Myusers1:index' %}"> Back to Home </a> </li></div>
{% endblock %}
不要忘记迁移，然后在admin.py 中注册模型。然后，您应该在数据库中创建一些人员，而很少有主管来尝试上述操作。我希望以上内容可以给您一些指导，以完成您的项目工作。我只想给你一个非常简单的例子。 （您必须创建所有其他必要的模板和视图）。
如果您创建了一个新的应用程序以尝试上述操作，则应在项目主urls.py文件中引用（包括）您的应用程序url，并在项目的urls.py文件中增加一行。然后，必须在应用程序的urls.py文件中定义所有新的应用程序URL：
主项目的urls.py如下所示：
urlpatterns = [
path('admin/', admin.site.urls),
path('myusers1/', include('Myusers1.urls')),
# so in your case:
path('myapp/', include('myapp.urls')),
]
（您必须将Myusers1更改为您的应用名称，）
当然，我们可以使用Django中的模型管理器做很多其他事情： https://docs.djangoproject.com/en/2.1/topics/db/managers/