How to make 1:N orm? use prefetch_related? - django

Question

template.html
{% for portfolioList in portfolio_list %}
<div class="jobster-timeline-item">
<div class="jobster-timeline-cricle">
<i class="far fa-circle"></i>
</div>
<div class="jobster-timeline-info">
<div class="dashboard-timeline-info">
<div class="dashboard-timeline-edit">
<ul class="list-unstyled d-flex">
<li><a class="text-right" href="{% url 'MyPortfolioUpdate' post_id=portfolioList.idx %}" role="button"> <i class="fas fa-pencil-alt text-info mr-2"></i> </a></li>
<li><i class="far fa-trash-alt text-danger"></i></li>
</ul>
</div>
<span class="jobster-timeline-time">{{portfolioList.start_date|date:"Y년 m월"}} ~ {{portfolioList.end_date|date:"Y년 m월"}}</span>
<h6 class="mb-2">{{portfolioList.subject}}</h6>
<span>-{{portfolioList.client_name}}</span>
<p class="mt-2">{{portfolioList.content|linebreaksbr}}</p>
<div class="row">
{% for portfolioImgList in portfolio_img_list %}
{% if portfolioImgList.portfolio_idx.idx == portfolioList.idx %}
<div class="col-md-6">
<img class="img-fluid" src="{{portfolioImgList.file.url}}" alt="" >
</div>
{% endif %}
{% endfor %}
</div>
</div>
</div>
</div>
{% endfor %}
view.py
q = Q()
q &= Q(user_idx = request.user.id)
portfolio_list = UserPortfolio.objects.filter(q).order_by('-idx')
q = Q()
q &= Q(portfolio_idx__user_idx = request.user.id)
portfolio_img_list = UserPortfolioFile.objects.filter(q).order_by('-idx')
return render(request, 'account/setting/portfolio_list.html', {"portfolio_list":portfolio_list, "portfolio_img_list":portfolio_img_list}
model.py
class UserPortfolio(models.Model):
idx = models.AutoField(primary_key=True)
user_idx = models.ForeignKey(
User,
db_column='user_idx',
on_delete=models.CASCADE
)
subject = models.CharField(max_length=255)
client_name = models.CharField(max_length=255)
client_service = models.CharField(max_length=255)
client_category = models.CharField(max_length=255)
start_date = models.DateTimeField()
end_date = models.DateTimeField()
content = models.TextField()
write_date = models.DateTimeField(auto_now = True)
update_date = models.DateTimeField(auto_now = True)
is_file = models.CharField(max_length=1)
class Meta:
managed = False
db_table = 'account_user_portfolio'
def portfolio_upload_to(instance, filename):
nowDate = datetime.now().strftime("%Y/%m/%d")
return '/'.join([str(instance.portfolio_idx.user_idx), instance.folder , nowDate, filename])
class UserPortfolioFile(models.Model):
idx = models.AutoField(primary_key=True)
portfolio_idx = models.ForeignKey(
UserPortfolio,
db_column='portfolio_idx',
on_delete=models.CASCADE
)
folder = 'portfolio'
file = models.ImageField(upload_to=portfolio_upload_to)
class Meta:
managed = False
db_table = 'account_user_portfolio_file'
This is result.
I want to use join orm in view.py. not like this. used 'if' in template.py
How can I do this? And I tried use join sql. but It was not worked.
I used prefetch_related this. but Its result was same as now.
And I think This is maybe good. doesn't?
Please answer something and thanks to every one

Answer 1

You can enumerate with .userportfoliofile_set.all:
{% for portfolioImgList in portfolioList.userportfoliofile_set.all %}
…
{% endfor %}
this will make a query to only retrieve the UserPortfolioFiles related to the portfolioList object.
In the view you can work with .prefetch_related(…) [Django-doc] to fetch all related items with one query, so:
def some_view(request):
portfolio_list = UserPortfolio.objects.filter(
user_idx=request.user.id
).prefetch_related('userportfoliofile_set').order_by('-idx')
return render(request, 'account/setting/portfolio_list.html', {'portfolio_list':portfolio_list})