使用Django中的表單更新數據庫行

Question

我正在嘗試使用Django的表單更新數據庫中的現有行。 創建新行沒有問題，但是當我嘗試更新現有行時，出現ValueError（帖子末尾的回溯）。

我知道我的“產品”屬性被誤認為是主鍵，但無法弄清楚原因。 這是我的代碼：

models.py

class Rates(models.Model):
    my_id = models.AutoField(primary_key=True)
    product = models.CharField(unique=True, max_length=255)
    taux_comm_1 = models.FloatField(blank=True, null=True)
    taux_comm_2 = models.FloatField(blank=True, null=True)
    taux_euros = models.FloatField(blank=True, null=True)
    taux_uc = models.FloatField(blank=True, null=True)
    taux_prud = models.FloatField(blank=True, null=True)

forms.py

class RatesForm(forms.ModelForm):
    class Meta:
        model = Rates
        fields = ['product', 'taux_comm_1', 'taux_comm_2', 'taux_euros', 'taux_uc', 'taux_prud']
        labels = {
            'product': "Nom du produit",
            'taux_comm_1': "Taux de commission de production",
            'taux_comm_2': "Taux de commission de portefeuille",
            'taux_euros': "Taux de commission sur l'encours euros",
            'taux_uc': "Taux de commission sur l'encours UC",
            'taux_prud': "Taux de commission sur l'encours UC Prudentes",
    }

     def __init__(self, *args, **kwargs):
        super(RatesForm, self).__init__(*args, **kwargs)
        self.fields['product'].widget.attrs.update({'class': 'form-control', 'readonly':'readonly'})
        self.fields['taux_comm_1'].widget.attrs.update({'class': 'form-control'})
        self.fields['taux_comm_2'].widget.attrs.update({'class': 'form-control'})
        self.fields['taux_euros'].widget.attrs.update({'class': 'form-control'})
        self.fields['taux_uc'].widget.attrs.update({'class': 'form-control'})
        self.fields['taux_prud'].widget.attrs.update({'class': 'form-control'})

views.py

 product = request.session['product']
 if request.method == 'POST':
     rates_form = RatesForm(request.POST)
     if rates_form.is_valid():
         rate = Rates.objects.get(pk=2)  
         rates_form = RatesForm(instance=rate)        
         rates_form.cleaned_data.get('product')
         rates_form.cleaned_data.get('taux_comm_1')
         rates_form.cleaned_data.get('taux_comm_2')
         rates_form.cleaned_data.get('taux_euros')
         rates_form.cleaned_data.get('taux_uc')
         rates_form.cleaned_data.get('taux_prud')
         rates_form.save()
         return redirect('/accountancy/rates/')
     else:
         search_form = SearchProduct()
         rate = Rates.objects.get(pk=2)  
         rates_form = RatesForm(instance=rate, initial={'product': product})

追溯

Traceback (most recent call last):
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/core/handlers/exception.py", line 35, in inner
     response = get_response(request)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/core/handlers/base.py", line 128, in 
     _get_response
     response = self.process_exception_by_middleware(e, request)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/core/handlers/base.py", line 126, in 
     _get_response
     response = wrapped_callback(request, *callback_args, 
     **callback_kwargs)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/contrib/auth/decorators.py", line 21, in 
     _wrapped_view
     return view_func(request, *args, **kwargs)
  File "/home/<3/vsc-workspace/ola/ola/accountancy/views.py", line 
     109, in view_update_rate
     'update': update,
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/shortcuts.py", line 36, in render
     content = loader.render_to_string(template_name, context, 
     request, 
     using=using)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/loader.py", line 62, in render_to_string
     return template.render(context, request)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/backends/django.py", line 61, in render
     return self.template.render(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 175, in render
     return self._render(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 167, in _render
     return self.nodelist.render(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 943, in render
     bit = node.render_annotated(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 910, in render_annotated
     return self.render(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/defaulttags.py", line 211, in render
     nodelist.append(node.render_annotated(context))
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 910, in render_annotated
     return self.render(context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 999, in render
     return render_value_in_context(output, context)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/template/base.py", line 978, in 
     render_value_in_context
     value = str(value)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/utils/html.py", line 380, in <lambda>
     klass.__str__ = lambda self: mark_safe(klass_str(self))
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/forms/boundfield.py", line 36, in __str__
     return self.as_widget()
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/forms/boundfield.py", line 118, in as_widget
     **kwargs
  File "/usr/local/lib/python3.5/dist- 
     packages/smart_selects/widgets.py", line 125, in render
     available_choices = self._get_available_choices(self.queryset, 
     value)
  File "/usr/local/lib/python3.5/dist- 
     packages/smart_selects/widgets.py", line 161, in 
     _get_available_choices
     item = queryset.filter(pk=value).first()
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/query.py", line 836, in filter
     return self._filter_or_exclude(False, *args, **kwargs)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/query.py", line 854, in 
     _filter_or_exclude
     clone.query.add_q(Q(*args, **kwargs))
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/sql/query.py", line 1253, in add_q
     clause, _ = self._add_q(q_object, self.used_aliases)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/sql/query.py", line 1277, in _add_q
     split_subq=split_subq,
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/sql/query.py", line 1215, in 
     build_filter
     condition = self.build_lookup(lookups, col, value)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/sql/query.py", line 1085, in 
     build_lookup
     lookup = lookup_class(lhs, rhs)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/lookups.py", line 18, in __init__
     self.rhs = self.get_prep_lookup()
  File "/home/<3/.local/lib/python3.5/site-                                                      
     packages/django/db/models/lookups.py", line 68, in 
     get_prep_lookup
     return self.lhs.output_field.get_prep_value(self.rhs)
  File "/home/<3/.local/lib/python3.5/site- 
     packages/django/db/models/fields/__init__.py", line 947, in 
     get_prep_value
     return int(value)
 ValueError: invalid literal for int() with base 10: 'Product A'

Django追溯

__class__   <class 'django.db.models.fields.AutoField'>
self    <django.db.models.fields.AutoField: id>
value   'Product A'

如果您有任何解決辦法，我將非常感謝您的幫助。

Answer 1

您似乎在會話中保存了文本值“ Product A”，而不是產品的實際ID。 如果您無法更改要保存的內容，則需要根據該名稱獲取產品實例。

但是您也認為自己在做一些非常奇怪的事情。 您不應該重新實例化表單，所有這些cleaned_data行絕對不執行任何操作。 另外，請注意縮進； else指向第一個if ，而不是第二個。

product = Product.objects.get(product_name=request.session['product']) # or whatever the name field is
rate = Rates.objects.get(pk=2)  
if request.method == 'POST':
    rates_form = RatesForm(request.POST, instance=rate)
    if rates_form.is_valid():
        rates_form.save()
        return redirect('/accountancy/rates/')
else:
    search_form = SearchProduct()
    rates_form = RatesForm(instance=rate, initial={'product': product})
return render(...)