在Django中使用查询的问题 [英] Issue with using query in Django

问题描述

所以我想要得到的是以下内容.用户可以选择代码中看到的3个类别.

So what I'm trying to get is the following. User can choose 3 categories as seen in the code.

在这些类别中，他们可以添加任意数量的植物.在我看来:集合我希望用户看到以下内容:

Inside those categories they can add any number of plants. In my view: collection I want the user to see the following:

收藏

用户选择的类别

• plant_1
• plant_2
• ....

Category_selected_by_user2

Category_selected_by_user2

我现在得到的是:

收藏

用户选择的类别

Category_selected_by_user2

Category_selected_by_user2

Category_selected_by_user3

Category_selected_by_user3

所以基本上这是models.py中的代码:

so basically this is the code in models.py:

class Plant_category(models.Model):
    """This class contains the users different categories"""
    CATEGORY_CHOICES = [
        ('Houseplant', 'Houseplant'),
        ('Succulents', 'Succulents'),
        ('Outdoor', 'Outdoor'),
    ]
    """Plural for multiple categories"""
    class Meta:
        verbose_name_plural = 'Categories'
        
    """Returns the above stated choices"""
    category = models.CharField(max_length=50, choices=CATEGORY_CHOICES)
    def __str__(self):
        return self.category

class Plant_name(models.Model):
    """This class contains the plant name that is housed within a certain category"""
    """Links the plant to one of the chosen categories"""
    category = models.ForeignKey(Plant_category, on_delete=models.CASCADE, related_name='plant_names')
    
    # Placeholder for connection with a plant database API
    plant = models.CharField(max_length=50)
    
    """Return the plant input from the user"""
    def __str__(self):
        return self.plant

这是views.py中的代码:

this is the code in views.py:

def collection(request):
    """The page that opens the collection of plants"""
    plant_categories = Plant_category.objects.all().order_by('category')
    
    
    context = {
        'plant_categories': plant_categories,
    }
    
    return render(request, 'plntz_main/collection.html', context)

这是collection.html中的代码:

And this is the code in collection.html:

<ul>
    {% for category in plant_categories %}
        <h3>{{ category }}</h3>
        {% for name in plant_categories.plant_names.all %}
            <li>{{ name.plant }}</li>
        {% endfor %}
    {% empty %}
        <li>No category has been added yet.</li>        
    {% endfor %}

</ul>

类别中工厂的提取数据一定有问题.我似乎找不到导致这种情况的原因.

There must be something wrong with the data pulled for the plants inside the category. I can't seem to find what is causing this.

例如，这是在室内植物"下添加的管理数据:

For example this is the admin data that has been added under Houseplant:

• houseplant_1
• houseplant_2

这是在多肉植物下添加的:

And this was added under Succulents:

• 仙人掌_1
• 仙人掌_2

推荐答案

这可能会导致问题:您没有正确地引用对象/查询集，因此不会在前端明智地呈现任何数据.

Imho this causes the problem: You don't refer to the object/queryset correctly, so no data is being rendered frontend wise.

您的上下文包含对象 plant_categories ，该对象应相应地循环:

Your context contains the object plant_categories which should be looped accordingly:

<ul>
{% for category in plant_categories %}
    <h3>{{ category }}</h3>

    # Refer to object within context
    {% for name in plant_categories %}

        <li>{{ name.plant }}</li> # Depending on what you would like to render you have to adapt here

    {% endfor %}
{% empty %}
    <li>No category has been added yet.</li>        
{% endfor %}

您可以在视图中添加打印语句以检查查询集:

You can add a print statement to your view to check the queryset:

def collection(request):
"""The page that opens the collection of plants"""
plant_categories = Plant_category.objects.all().order_by('category')


context = {
    'plant_categories': plant_categories,
}

# Print for debugging
print(plant_categories)

return render(request, 'plntz_main/collection.html', context)

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