Django IntegrityError-非空约束失败：学习\u日志\u主题.owner\u id 问题_Django_Python 3.6

Django IntegrityError-非空约束失败：学习\u日志\u主题.owner\u id 问题

django

Django IntegrityError-非空约束失败：学习\u日志\u主题.owner\u id 问题,django,python-3.6,Django,Python 3.6,大家好，我正在制作一个名为“学习日志”的项目，您可以在其中创建新主题并添加与特定主题相关的条目。我有个问题；当我尝试添加新主题时，屏幕上会弹出一个IntegrityError。设置用户身份验证和注册系统后，它会在我的views.py中不断突出显示代码：form.save（）。这是我得到的回溯： Exception Type: IntegrityError at /new_topic/ Exception Value: NOT NULL constraint failed: learni

大家好，我正在制作一个名为“学习日志”的项目，您可以在其中创建新主题并添加与特定主题相关的条目。我有个问题；当我尝试添加新主题时，屏幕上会弹出一个

IntegrityError

。设置用户身份验证和注册系统后，它会在我的

views.py

中不断突出显示代码：

form.save（）

。这是我得到的回溯：

    Exception Type: IntegrityError at /new_topic/
Exception Value: NOT NULL constraint failed: learning_logs_topic.owner_id

代码我的

views.py

如下所示：

from django.shortcuts import render
from django.http import HttpResponseRedirect, Http404
from django.urls import reverse
from django.contrib.auth.decorators import login_required

from .models import Topic, Entry
from .forms import TopicForm, EntryForm

def index(request):
    """The Home Page for Learning Log."""
    return render(request, 'learning_logs/index.html')

@login_required
def topics(request):
    """Show all topics."""
    topics = Topic.objects.filter(owner=request.user).order_by('date_added')
    context = {'topics': topics}
    return render(request, 'learning_logs/topics.html', context)

@login_required
def topic(request, topic_id):
    """Show a single topic and all its entries."""
    topic = Topic.objects.get(id=topic_id)
    # Make sure the Topic belongs to the current user.
    if topic.owner != request.user:
        raise Http404

    entries = topic.entry_set.order_by('-date_added')
    context = {'topic': topic, 'entries': entries}
    return render(request, 'learning_logs/topic.html', context)

@login_required
def new_topic(request):
    """Add a new topic."""
    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = TopicForm()
    else:
        # POST data submitted; process data.
        form = TopicForm(data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topics'))

    context = {'form': form}
    return render(request, 'learning_logs/new_topic.html', context)

@login_required
def new_entry(request, topic_id):
    """Add a new entry for the particular topic."""
    topic = Topic.objects.get(id=topic_id)

    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = EntryForm()
    else:
        # POST data submitted; process data.
        form = EntryForm(data=request.POST)
        if form.is_valid():
            new_entry = form.save(commit=False)
            new_entry.topic = topic
            new_entry.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic_id]))

    context = {'topic': topic, 'form': form}
    return render(request, 'learning_logs/new_entry.html', context)

@login_required
def edit_entry(request, entry_id):
    """Edit an existing entry."""
    entry = Entry.objects.get(id=entry_id)
    topic = entry.topic
    if topic.owner != request.user:
        raise Http404

    if request.method != 'POST':
        # Initial request; pre-fill form with the current entry.
        form = EntryForm(instance=entry)
    else:
        # POST data submitted; process data.
        form = EntryForm(instance=entry, data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic.id]))

    context = {'entry': entry, 'topic': topic, 'form': form}
    return render(request, 'learning_logs/edit_entry.html', context)

from django import forms

from .models import Topic, Entry

class TopicForm(forms.ModelForm):
    class Meta:
        model = Topic
        fields = ['text']
        labels = {'text': ''}

class EntryForm(forms.ModelForm):
    class Meta:
        model = Entry
        fields = ['text']
        labels = {'text': ''}
        widgets = {'text': forms.Textarea(attrs={'cols': 80})}

from django.db import models
from django.contrib.auth.models import User

class Topic(models.Model):
    """A topic the user is learning about."""
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User, on_delete=models.CASCADE)

    def __str__(self):
        """Return a string representation of the model."""
        return self.text

class Entry(models.Model):
    """Something specific learned about a topic."""
    topic = models.ForeignKey(Topic, on_delete=models.CASCADE)
    text = models.TextField()
    date_added = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = 'entries'

    def __str__(self):
        """Return a string representation of the model."""
        # Add an ellipsis ONLY if the entry,
        # is more than 50 characters long.
        if self.text > self.text[:50]:
            return self.text[:50] + "..."
        elif self.text <= self.text[:50]:
            return self.text[:50]

我的

forms.py

如下所示：

from django.shortcuts import render
from django.http import HttpResponseRedirect, Http404
from django.urls import reverse
from django.contrib.auth.decorators import login_required

from .models import Topic, Entry
from .forms import TopicForm, EntryForm

def index(request):
    """The Home Page for Learning Log."""
    return render(request, 'learning_logs/index.html')

@login_required
def topics(request):
    """Show all topics."""
    topics = Topic.objects.filter(owner=request.user).order_by('date_added')
    context = {'topics': topics}
    return render(request, 'learning_logs/topics.html', context)

@login_required
def topic(request, topic_id):
    """Show a single topic and all its entries."""
    topic = Topic.objects.get(id=topic_id)
    # Make sure the Topic belongs to the current user.
    if topic.owner != request.user:
        raise Http404

    entries = topic.entry_set.order_by('-date_added')
    context = {'topic': topic, 'entries': entries}
    return render(request, 'learning_logs/topic.html', context)

@login_required
def new_topic(request):
    """Add a new topic."""
    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = TopicForm()
    else:
        # POST data submitted; process data.
        form = TopicForm(data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topics'))

    context = {'form': form}
    return render(request, 'learning_logs/new_topic.html', context)

@login_required
def new_entry(request, topic_id):
    """Add a new entry for the particular topic."""
    topic = Topic.objects.get(id=topic_id)

    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = EntryForm()
    else:
        # POST data submitted; process data.
        form = EntryForm(data=request.POST)
        if form.is_valid():
            new_entry = form.save(commit=False)
            new_entry.topic = topic
            new_entry.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic_id]))

    context = {'topic': topic, 'form': form}
    return render(request, 'learning_logs/new_entry.html', context)

@login_required
def edit_entry(request, entry_id):
    """Edit an existing entry."""
    entry = Entry.objects.get(id=entry_id)
    topic = entry.topic
    if topic.owner != request.user:
        raise Http404

    if request.method != 'POST':
        # Initial request; pre-fill form with the current entry.
        form = EntryForm(instance=entry)
    else:
        # POST data submitted; process data.
        form = EntryForm(instance=entry, data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic.id]))

    context = {'entry': entry, 'topic': topic, 'form': form}
    return render(request, 'learning_logs/edit_entry.html', context)

from django import forms

from .models import Topic, Entry

class TopicForm(forms.ModelForm):
    class Meta:
        model = Topic
        fields = ['text']
        labels = {'text': ''}

class EntryForm(forms.ModelForm):
    class Meta:
        model = Entry
        fields = ['text']
        labels = {'text': ''}
        widgets = {'text': forms.Textarea(attrs={'cols': 80})}

from django.db import models
from django.contrib.auth.models import User

class Topic(models.Model):
    """A topic the user is learning about."""
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User, on_delete=models.CASCADE)

    def __str__(self):
        """Return a string representation of the model."""
        return self.text

class Entry(models.Model):
    """Something specific learned about a topic."""
    topic = models.ForeignKey(Topic, on_delete=models.CASCADE)
    text = models.TextField()
    date_added = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = 'entries'

    def __str__(self):
        """Return a string representation of the model."""
        # Add an ellipsis ONLY if the entry,
        # is more than 50 characters long.
        if self.text > self.text[:50]:
            return self.text[:50] + "..."
        elif self.text <= self.text[:50]:
            return self.text[:50]

我的

models.py

如下所示：

from django.shortcuts import render
from django.http import HttpResponseRedirect, Http404
from django.urls import reverse
from django.contrib.auth.decorators import login_required

from .models import Topic, Entry
from .forms import TopicForm, EntryForm

def index(request):
    """The Home Page for Learning Log."""
    return render(request, 'learning_logs/index.html')

@login_required
def topics(request):
    """Show all topics."""
    topics = Topic.objects.filter(owner=request.user).order_by('date_added')
    context = {'topics': topics}
    return render(request, 'learning_logs/topics.html', context)

@login_required
def topic(request, topic_id):
    """Show a single topic and all its entries."""
    topic = Topic.objects.get(id=topic_id)
    # Make sure the Topic belongs to the current user.
    if topic.owner != request.user:
        raise Http404

    entries = topic.entry_set.order_by('-date_added')
    context = {'topic': topic, 'entries': entries}
    return render(request, 'learning_logs/topic.html', context)

@login_required
def new_topic(request):
    """Add a new topic."""
    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = TopicForm()
    else:
        # POST data submitted; process data.
        form = TopicForm(data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topics'))

    context = {'form': form}
    return render(request, 'learning_logs/new_topic.html', context)

@login_required
def new_entry(request, topic_id):
    """Add a new entry for the particular topic."""
    topic = Topic.objects.get(id=topic_id)

    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = EntryForm()
    else:
        # POST data submitted; process data.
        form = EntryForm(data=request.POST)
        if form.is_valid():
            new_entry = form.save(commit=False)
            new_entry.topic = topic
            new_entry.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic_id]))

    context = {'topic': topic, 'form': form}
    return render(request, 'learning_logs/new_entry.html', context)

@login_required
def edit_entry(request, entry_id):
    """Edit an existing entry."""
    entry = Entry.objects.get(id=entry_id)
    topic = entry.topic
    if topic.owner != request.user:
        raise Http404

    if request.method != 'POST':
        # Initial request; pre-fill form with the current entry.
        form = EntryForm(instance=entry)
    else:
        # POST data submitted; process data.
        form = EntryForm(instance=entry, data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('learning_logs:topic',
                                                args=[topic.id]))

    context = {'entry': entry, 'topic': topic, 'form': form}
    return render(request, 'learning_logs/edit_entry.html', context)

from django import forms

from .models import Topic, Entry

class TopicForm(forms.ModelForm):
    class Meta:
        model = Topic
        fields = ['text']
        labels = {'text': ''}

class EntryForm(forms.ModelForm):
    class Meta:
        model = Entry
        fields = ['text']
        labels = {'text': ''}
        widgets = {'text': forms.Textarea(attrs={'cols': 80})}

from django.db import models
from django.contrib.auth.models import User

class Topic(models.Model):
    """A topic the user is learning about."""
    text = models.CharField(max_length=200)
    date_added = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User, on_delete=models.CASCADE)

    def __str__(self):
        """Return a string representation of the model."""
        return self.text

class Entry(models.Model):
    """Something specific learned about a topic."""
    topic = models.ForeignKey(Topic, on_delete=models.CASCADE)
    text = models.TextField()
    date_added = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = 'entries'

    def __str__(self):
        """Return a string representation of the model."""
        # Add an ellipsis ONLY if the entry,
        # is more than 50 characters long.
        if self.text > self.text[:50]:
            return self.text[:50] + "..."
        elif self.text <= self.text[:50]:
            return self.text[:50]

来自django.db导入模型的


从django.contrib.auth.models导入用户
课程主题（models.Model）：
“”“用户正在学习的主题。”“”
text=models.CharField（最大长度=200）
date\u added=models.DateTimeField（auto\u now\u add=True）
owner=models.ForeignKey（用户，on_delete=models.CASCADE）
定义（自我）：
“”“返回模型的字符串表示形式。”“”
返回self.text
类条目（models.Model）：
“”“有关某个主题的特定知识。”“”
topic=models.ForeignKey（topic，on_delete=models.CASCADE）
text=models.TextField（）
date\u added=models.DateTimeField（auto\u now\u add=True）
类元：
详细名称复数='entries'
定义（自我）：
“”“返回模型的字符串表示形式。”“”
#仅当条目，
#长度超过50个字符。
如果self.text>self.text[：50]：
返回self.text[：50]+“…”
elif self.text这是我对这个问题的答案，我已经知道了
Django返回一个IntegrityError
，因为您没有将新主题与任何特定用户关联。这意味着如果不为主题的owner字段指定值，就无法创建新主题。
这个问题有一个简单的解决方案，因为您可以访问通过请求
对象登录的当前用户。为了解决这个问题，我只需将新主题
保存到一个变量中，并将其与当前登录的用户关联，然后将更改保存到数据库中
更新视图.py中的新主题（）
：
@login_required
def new_topic(request):
    """Add a new topic."""
    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = TopicForm()
    else:
        # POST data submitted; process data.
        form = TopicForm(data=request.POST)
        if form.is_valid():
            new_topic = form.save(commit=False) # Save topic in a variable.
            new_topic.owner = request.user # Set topics owner attribute to current user.
            new_topic.save() # Save the changes to the database.
            return HttpResponseRedirect(reverse('learning_logs:topics'))

我也有这个问题，但更进一步，他们在书中给出了答案：
将新主题与当前用户关联当前，用于添加新主题的页面已断开，因为它不会将新主题与任何特定用户关联。如果尝试添加新主题，将看到错误消息IntegrityError以及学习日志主题。用户id不能为NULL。Django说，如果不为主题的所有者字段指定一个值，就无法创建新主题。这个问题有一个简单的解决方法，因为我们可以通过请求对象访问当前用户。添加以下代码，将新主题与当前用户关联：
views.py
对于Django 2.2：
@login_required
def new_topic(request):
    """Add a new topic."""
    if request.method != 'POST':
        # No data submitted; create a blank form.
        form = TopicForm()
    else:
         # POST data submitted; process data.
        form = TopicForm(data=request.POST)
        if form.is_valid():
            new_topic = form.save(commit=False)
            new_topic.owner = request.user
            new_topic.save()
            return redirect('learning_logs:topics')

    # Return an empty or invalid form.
    context = {'form': form}
    return render(request, 'learning_logs/new_topic.html', context)