CODEWITHSUNDEEP
djangodjango-templates
kjarsenal
kjarsenal

Reputation: 934

foriegn key object not iterable in template

I have basic models for a section, subsection and clause. 1 section can hold multiple subsections. Each subsection can hold multiple clauses. The models look like:

**models.py**

class Clause(models.Model):
    number = models.CharField(max_length=8, unique=True)
    requirements = models.TextField(max_length=2000, unique=False, blank=True, null=True)
    documentation = models.TextField(max_length=2000, unique=False, blank=True, null=True) 

class Subsection(models.Model):
    number = models.CharField(max_length=5, unique=True)
    name = models.CharField(max_length=150, unique=False)
    descriptor = models.TextField(max_length=2000, unique=False, blank=True, null=True)
    clause = models.ForeignKey(Clause, on_delete=models.DO_NOTHING, related_name="clause")

class Section(models.Model):
    number = models.CharField(max_length=2, unique=True)
    name = models.CharField(max_length=150, unique=False)
    descriptor = models.TextField(max_length=2000, unique=False, blank=True, null=True)
    subsection = models.ForeignKey(Subsection, on_delete=models.DO_NOTHING, related_name="subsection")

basic view function to call the desired section:

**views.py**

def main(request):
    form = MainSearchForm() 
    user = request.user
    sections = []

    show_results = True
    if 'query' in request.GET:
            show_results = True
            query = request.GET['query'].strip()
            if len(query) <= 2:
                sections = Section.objects.filter(number__iexact=query) 

    if    sections: 
            records = sections
            tpl = "display_console.html"
            context = {'user': user, 'records': records, 'form': form}
            return render(request, tpl, context)

    else:
            tpl = "main.html"
            context = {'user': user, 'form': form}
            return render(request, tpl, context)

unfortunately, I can't get my template to return my subsection data. The following returns a 'Subsection' object is not iterable error:

**template**

<table class="section_tb">

            {% if records %}
       {% for record in records %}

    <tr>
        <td>{{ record.number }}</td><td>{{ record.name }}</td>
    </tr>

    {% for item in record.subsection %}

    <tr>
        <td>{{ item.number }}</td><td>{{ item.name }}</td>
    </tr>
    <tr>
        <td colspan=2>{{ item.descriptor }}</td>
    </tr>
             {% endfor %}
</table>

             {% endfor %}
             {% else %}
             {% endif %}

substituting:

{% for item in record.subsection.all %}

for:

{% for item in record.subsection %}

removes the error message, but doesn't return any data. Is there something obvious I'm doing wrong?

Upvotes: 0

Views: 237

Answers (1)

Ben Boyer
Ben Boyer

Reputation: 1234

This is because Section can have only one Subsection. So you can access the subsection with just {{record.subsection}} so no forloop needed here.

As a tip remember when you usea one to many, the one is where the foreign key is defined. The model that store the foreign key will always store only one foreign key.

If you want to access the many foreign keys from the other side use the model_name_in_lowercase_set or define a related name in models.ForeignKey(..., related_name="something") then you can call something_set

Upvotes: 1

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