无法分配“u”“”：“Company.parent”必须是“公司”例 [英] Cannot assign "u''": "Company.parent" must be a "Company" instance

问题描述

无法分配u：Company.parent必须是公司实例。
我不知道还有什么要做的。
视图代码仍然是半烤，对不起。
我是否将错误的参数传递给表单？

我有以下模型：

。

  class Company（AL_Node）：
 parent = models.ForeignKey（'self'，
 related_name ='children_set'，
 null = True，
 db_index = True）
 node_order_by = ['id'，'company_name'] 
 id = models.AutoField（primary_key = True ）
 company_name = models.CharField（max_length = 100L，db_column ='company_name'）＃字段名称小写。 
 next_billing_date = models.DateTimeField（）
 last_billing_date = models.DateTimeField（null = True）
 weekly ='we'
 two_a_month ='2m'
 every_two_weeks =' 2w'
 monthly ='mo'
 billing_period_choices =（
（weekly，'Weekly'），
（every_two_weeks，'每两周'），
（two_a_month ，每两周），
（每月，每月），
）
 billing_period = models.CharField（max_length = 2，
 choices = billing_period_choices，
 default = weekly）
 
 objects = CompanyManager（）
  

以下表单.py：

  class newCompany（ModelForm）：
 company_name = forms.CharField（label ='Company Name' 
 widget = forms.TextInput（attrs = {'class'：'oversize expand input-text'}））
 billing_period = forms.ModelChoiceFie ld 
 next_billing_date = forms.CharField（widget = forms.TextInput（attrs = {'class'：'input-text small'，'id'：'datepicker'}））
 parent = forms.CharField （widget = forms.HiddenInput（），required = False）
 
 class Meta：
 model = Company 
 fields = [company_name，parent，billing_period next_billing_date] 
  

以下视图：

  def create_company（request）：
 userid = User.objects.get（username = request.user）.id 
 my_company_id = CompanyUsers.objects.get（user_id = userid）.company_id 
 my_company_name = Company.objects.get（id = my_company_id）.company_name 
 machines = Title.objects.raw（
'select machines.id，title.name，machines （.moneyin，machines.moneyout，moneyin-moneyout as profit，machines.lastmoneyinoutupdate）（从auth_user中选择auth_user.username，其中machines.operator = auth_user.id）作为运算符，（从auth_user选择auth_user.username，其中machi nes.readers = auth_user.id）作为读取器从机器，标题在哪里machines.title = title.id和machines.company_id =％s'，
 [my_company_id]）
如果request.method ==' POST'：
 form_company = newCompany（request.POST）
如果form_company.is_valid（）：
 new_company = form_company.save（commit = False）
 new_company.parent = my_company_id 
如果request.POST.get（'select_machine'）：
 selected_machine = request.POST.getlist（'select_machine'）
 percent = request.POST.get（'percentage'）
如果不是Beneficiary.objects.check_assign_machine（my_company_id，selected_machine，percentage）：
 target_company_name = new_company.company_name 
 target_company_id = Company.objects.get（company_name = target_company_name）.id 
 new_company.save （）
 Machines.objects.assign_machine（target_company_id，selected_machine）
 Beneficiary.objects.create_benef iciary（percent，target_company_name，my_company_id，selected_machine）
 else：
 invalid_machines = Beneficiary.objects.check_assign_machine（my_company_id，selected_machine，percentage）
 return render（request，'lhmes / createcompany.html' ，
 {'form_company'：form_company，'machines'：machines，'my_company_name'：my_company_name，'invalid_machines'：invalid_machines}）
 else：
 new_company.save（）
 
 else：
 form_company = newCompany（）
 
 return render（request，'lhmes / createcompany.html'，
 {'form_company'：form_company，'machines' ：机器'my_company_name'：my_company_name}）
  

解决方案

错误消息表示您正在尝试与字符串建立关系，但Django希望该值成为公司模型的一个实例。您应该为外键字段分配一个真正的模型实例，而不是仅将主键分配。

我在代码中发现了几个分配PK的地方：

  new_company.parent = my_company_id 
  

模型希望它是一个实例：

  new_company.parent = Company.objects .get（id = my_company_id）
  

我真的不记得如果这样， ：

  new_company.parent_id = int（my_company_id）
  

这将免去数据库的旅行。

I am getting this at every attempt.

Cannot assign "u''": "Company.parent" must be a "Company" instance. I do not know what else to do. The view code is still half baked, sorry for that. Am I passing wrong parameters to the form?

I have the following model:

models.py

class Company(AL_Node):
  parent = models.ForeignKey('self',
                             related_name='children_set',
                             null=True,
                             db_index=True)
  node_order_by = ['id', 'company_name']
  id = models.AutoField(primary_key=True)
  company_name = models.CharField(max_length=100L, db_column='company_name') # Field name made lowercase.
  next_billing_date = models.DateTimeField()
  last_billing_date = models.DateTimeField(null=True)
  weekly = 'we'
  twice_a_month = '2m'
  every_two_weeks = '2w'
  monthly = 'mo'
  billing_period_choices = (
    (weekly, 'Weekly'),
    (every_two_weeks, 'Every two weeks'),
    (twice_a_month, 'Every two weeks'),
    (monthly, 'Monthly'),
  )
  billing_period = models.CharField(max_length=2,
                                    choices=billing_period_choices,
                                    default=weekly)

  objects = CompanyManager()

The following forms.py:

class newCompany(ModelForm):
  company_name = forms.CharField(label='Company Name',
                                widget=forms.TextInput(attrs={'class': 'oversize expand input-text'}))
  billing_period = forms.ModelChoiceField
  next_billing_date = forms.CharField(widget=forms.TextInput(attrs={'class': 'input-text small', 'id': 'datepicker'}))
  parent = forms.CharField(widget=forms.HiddenInput(), required=False)

  class Meta:
    model = Company
    fields = ["company_name", "parent", "billing_period", "next_billing_date"]

The following view:

def create_company(request):
  userid = User.objects.get(username=request.user).id
  my_company_id = CompanyUsers.objects.get(user_id=userid).company_id
  my_company_name = Company.objects.get(id=my_company_id).company_name
  machines = Title.objects.raw(
    'select machines.id, title.name, machines.moneyin, machines.moneyout, moneyin - moneyout as profit, machines.lastmoneyinoutupdate, (select auth_user.username from auth_user where machines.operator = auth_user.id) as operator, (select auth_user.username from auth_user where machines.readers = auth_user.id) as readers from machines, title where machines.title = title.id and machines.company_id =%s',
    [my_company_id])
  if request.method == 'POST':
    form_company = newCompany(request.POST)
    if form_company.is_valid():
      new_company = form_company.save(commit=False)
      new_company.parent = my_company_id
      if request.POST.get('select_machine'):
        selected_machine = request.POST.getlist('select_machine')
        percentage = request.POST.get('percentage')
        if not Beneficiary.objects.check_assign_machine(my_company_id, selected_machine, percentage):
           target_company_name = new_company.company_name
           target_company_id = Company.objects.get(company_name=target_company_name).id
           new_company.save()
           Machines.objects.assign_machine(target_company_id, selected_machine)
           Beneficiary.objects.create_beneficiary(percentage, target_company_name, my_company_id, selected_machine)
        else:
          invalid_machines = Beneficiary.objects.check_assign_machine(my_company_id, selected_machine, percentage)
          return render(request, 'lhmes/createcompany.html',
                {'form_company': form_company, 'machines': machines, 'my_company_name': my_company_name, 'invalid_machines' : invalid_machines})
      else:
        new_company.save()

  else:
    form_company = newCompany()

  return render(request, 'lhmes/createcompany.html',
                {'form_company': form_company, 'machines': machines, 'my_company_name': my_company_name})

解决方案

The error message says you are trying to set a relationship with a string but Django expects the value to be an instance of the Company model. You should assign the foreign key fields with a real model instance instead of only the primary key.

I've spotted a few places in the code where you are assigning a PK:

new_company.parent = my_company_id

Where the model expects it to be an instance:

new_company.parent = Company.objects.get(id=my_company_id)

I really don't remember if this works, but you can try:

new_company.parent_id = int(my_company_id)

This would spare a trip to the database.

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