如何获得在 Django 中使用模型关系的次数？

Question

I have 2 models 1 is Job Model which is something like this

class Job(models.Model):
    name=models.CharField(max_length=500,null=False,blank=False)
    description=models.TextField(max_length=5000,null=True,blank=True)
    slug=AutoSlugField(populate_from='name',null=True, blank=True)
    industry=models.ForeignKey('Industry',null=True, blank=True, on_delete=models.SET_NULL)

and other model is Industry model. This model has one to one relation with Job model Industry model is like this

class Industry(models.Model):
    name=models.CharField(max_length=2000,null=True, blank=True)

Now what i'm trying to do is to get count of jobs against each indsutry using industry model like this

{% for industry in industry_2 %}
                      <li><a href="#"><h6 class="category-title">{{ industry.name }}</h6> <span class="category-count">{{ industry.jobs_count }}</span> </a></li>
                      {% endfor %}

but its not working for me, please help me in this regard to solve this issue. Do suggest any better method also, Thanks

Answer 1

you can use

{% for industry in industry_2 %}
    <li><a href="#"><h6 class="category-title">{{ industry.name }}</h6> <span class="category-count">{{ industry.job_set.count }}</span> </a></li>
{% endfor %}

Please, note that by default, ie if you do not use related_name on a ForeignKey , the related name is lowercased model name suffixed with _set , which makes sense, it's a job set of an industry.