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python - 无法在 Django 外键字段中插入值

问题描述

我试图在 django 的外键字段中插入值。但它向我展示了这样的错误：- 无法分配“'95'”：“Catalog.author_id”必须是“作者”实例。 但是当我尝试使用 django shell 插入时，它没有显示任何错误，它工作正常。请帮帮我我附上了我的代码，你可以很好地理解

模型.py

class Author(models.Model):
    author_id = models.CharField(max_length=50, primary_key=True)
    name = models.CharField(max_length=50)
    city = models.CharField(max_length=50)
    country = models.CharField(max_length=50)

    def __str__(self):
        return str(self.author_id)


class Catalog(models.Model):
    book_id = models.IntegerField(primary_key=True)
    title = models.CharField(max_length=100)
    year_of_publish = models.CharField(max_length=5)
    price = models.IntegerField()
    author_id = models.ForeignKey('Author', on_delete=models.CASCADE, null=True)

    def __str__(self):
        return str(self.book_id)

表格.py

class Catalog_Details(forms.ModelForm):
book_id = forms.CharField(widget=forms.TextInput(
    attrs={'class': 'form-control',
           'placeholder': 'Enter book id'}
), required=True, max_length=50)

title = forms.CharField(widget=forms.TextInput(
    attrs={'class': 'form-control',
           'placeholder': 'Enter title'}
), required=True, max_length=50)
year_of_publish = forms.CharField(widget=forms.TextInput(
    attrs={'class': 'form-control',
           'placeholder': 'Enter Published Year'}
), required=True, max_length=5)
author_id = forms.ModelChoiceField(queryset=Author.objects.values_list(
    'author_id', flat=True))

price = forms.CharField(widget=forms.TextInput(
    attrs={'class': 'form-control',
           'placeholder': 'Enter Price'}
), required=True, max_length=50)

class Meta():
    model = Catalog
    fields = ['book_id', 'title', 'year_of_publish', 'price', 'author_id']

视图.py

@login_required
def catalog(request):
    if request.user.is_authenticated:
        if request.method == 'POST':
            form = Catalog_Details(request.POST)
            if form.is_valid():
                author_id = form.cleaned_data['author_id']
                m = Author.objects.get(author_id=author_id)
                c1 = Catalog(book_id=form.cleaned_data['book_id'], title=form.cleaned_data['title'],
                           year_of_publish=form.cleaned_data['year_of_publish'],price=form.cleaned_data['price'], author_id=m)
                c1.save()
                form = Catalog_Details()

        else:
            form = Catalog_Details()
        return render(request, 'catalog.html', {'form': form})

标签： pythondjangodjango-modelsdjango-formsdjango-views

解决方案

我认为甚至没有必要覆盖author_id表单中的字段。您可以author_id从Catalog_Details. 你可以像这样更新你的视图：

@login_required
def catalog(request):
    if request.method == 'POST':
        form = Catalog_Details(request.POST)
        if form.is_valid():
            form.save()
            form = Catalog_Details()
            # here you should redirect to a success page to know `Catalog_Details` has been created
    else:
        form = Catalog_Details()
    return render(request, 'catalog.html', {'form': form})

仅供参考，您不应ForeignKey使用 suffix 命名字段_id，因为 django 会为您创建它。例如：在您的情况下，您会author_id_id在Catalog模型中找到一个字段，该字段将返回一个整数值（作者表列的主键）。

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