Django: Access model field with two keys in template-CodePudding

I am a bit lost. It is been a while since I did some Django and I almost forgot everything about querysets and template. The app is a questionaire for comparing different vendors - hence their products. It is a questionaire with a scoring (best match) to each product.

I want to access a specific element in a for loop which has two foreign keys to other classes. Here my model:

Model:

class Question(models.Model):
    questionText = models.CharField(max_length=500)

class Vendor(models.Model):
    vendorName = models.CharField(max_length=30, unique=True)

class Scoring(models.Model):        
    score = models.IntegerField(default='0', blank=True)
    questionScoreForKey = models.ForeignKey(Question, null=True, related_name='scorequestion', on_delete=models.SET_NULL)
    vendorForKey = models.ForeignKey(Vendor, null=True, related_name='scorevendor', on_delete=models.SET_NULL)

views.py

def index(request):
    questions = Question.objects.all()
    vendors = Vendor.objects.all()
    return render(request, 'compare/index.html', {'questions': questions, 'vendors': vendors})

Template

{% for ask in questions %}
<tr>
  <td>{{ ask.questionText }}  </td>
    {% for vend in vendors %}
    <td id="Vendor_{{ ask.pk }}_{{ vend.pk }}" style> {{ HERE THE SCORE OF THE QUESTION AND VENDOR  }}  </td> 
    {% endfor %}
</tr>
{% endfor %}

Both keys are existing but I have no clue how to access the score of e. g. the first question for the first vendors. Any hint appreciated.

CodePudding user response：

You need to reverse query the scores. Since you've defined related names in your models, you can use them.

Note that a reverse query gives you a manager object. The all method returns a queryset with all objects matching the reverse query (you defined a one-to-many relationship, one question/vendor can have many scores). Then further filter the queryset to get the instance you need (e.g. first).

{{vendor.scorevendor.all.first.score}}