/listing/1/NOTNULL約束處??的IntegrityError失敗：auctions_comments.user_id。我正在嘗試保存評論并需要幫助解決此錯誤

我正在嘗試制作一個保存評論的電子商務網站（CS50 專案 2）。評論之前是保存的，但后來我將 ForeignKeys 添加到我的評論模型中以將其鏈接到 Listings 和 User 模型。現在，每當我嘗試保存評論時，都會發生此錯誤。

IntegrityError at /listing/1/
NOT NULL constraint failed: auctions_comments.user_id
Request Method: POST
Request URL:    http://127.0.0.1:8000/listing/1/
Django Version: 3.2.5
Exception Type: IntegrityError
Exception Value:    
NOT NULL constraint failed: auctions_comments.user_id

并且這行代碼被高亮了comment.save()。

這是我的models.py：

class User(AbstractUser):
    pass

class Listings(models.Model):
    CATEGORY = [
    ("Miscellaneous", "Miscellaneous"),
    ("Movies and Television", "Movies and Television"),
    ("Sports", "Sports"),
    ("Arts and Crafts", "Arts and Crafts"),
    ("Clothing", "Clothing"),
    ("Books", "Books"),
]
    title = models.CharField(max_length=64)
    description = models.CharField(max_length=500)
    bid = models.DecimalField(max_digits=1000000000000, decimal_places=2)
    image = models.URLField(null=True, blank=True)
    category = models.CharField(max_length=64, choices=CATEGORY, default=None)

class Comments(models.Model):
    listing = models.ForeignKey(Listings, on_delete=models.CASCADE, default="")
    user = models.ForeignKey(User, on_delete=models.CASCADE, default="")
    comment = models.CharField(max_length=500)

視圖.py

@login_required(login_url='login')
def listing(request, id):
    listing = Listings.objects.get(id=id)
    comment_obj = Comments.objects.filter(listing=listing)
    form = CommentForm()
    if request.method == "POST":
        form = CommentForm(request.POST)
        if form.is_valid():
            comment = form.save(commit=False)
            comment.listing = listing
            comment.save()
        else:
            return render(request, "auctions/listing.html",{
               "auction_listing": listing,
               "form": form,
               "comments": comment_obj
               })
    return render(request, "auctions/listing.html",{
        "auction_listing": listing,
        "form": form,
        "comments": comment_obj
    })

html

{% block body %}
    <img src ="{{ auction_listing.image }}" style = "height: 10%; width: 10%;">
    <h4 class = "text">{{ auction_listing.title }}</h4>
    <h6>Description: {{ auction_listing.description }}</h6>
    <h6>Category: {{ auction_listing.category }}</h6> 
    <h6>Price: ${{ auction_listing.bid }}</h6>

    <form action = "{% url 'listing' auction_listing.id %}" method = "POST">
        {% csrf_token %}
        {{ form }}
        <input type = "submit" value = "Save">
    </form>

    {% for comment in comments %}
        <h6> {{ comment.comment }} </h6>
    {% endfor %}

    <button type = "button">Add to Watchlist</button>
{% endblock %}

我認為問題在于views.py中的comment.save（）和html中的表單，其中顯示“{% url'listing'auction_listing.id %}”，但我不知道如何解決它.

謝謝大家的幫助！

表格.py

class ListingsForm(forms.ModelForm):
    class Meta:
        model = Listings
        fields = ['title', 'description', 'bid', 'image', 'category']

class CommentForm(forms.ModelForm):
    class Meta:
        model = Comments
        fields = ['comment']

uj5u.com熱心網友回復：

我假設用戶用來發表評論的表單沒有讓他們指定他們的listingID 或userID。如果是這種情況，那么兩者listing和userinComments都將為 null，這是導致錯誤的原因，因為不允許外鍵為 null。您必須在視圖中手動填寫這些缺失的資料。看起來您已經確定了串列值并將其添加到表單實體中。你只需要為用戶做同樣的事情。該request引數有一個user欄位，您可以使用它來計算userID。

if form.is_valid():
            comment = form.save(commit=False)
            comment.listing = listing
            comment.user = request.user
            comment.save()

標籤：Python django 形式 django模型 cs50

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