Thank you Matthew. Excellent advise as always. When I started off with this
project 5 months ago, I was a beginner to both django and python. I've come
a bit along the journey. That customer model is the first model I created,
and I was unaware of these conventions. By the time I realized that, the
project has branched into several apps, and the code now runs into
thousands of lines of code. I didnt change the naming due to fear of
breaking other code. :)
Nowadays I do it more "pythonically". Still, it's great to have people like
you offer excellent general advise to help budding enthusiasts!
Sincerely yours,
Joel G Mathew
On Tue, 30 Apr 2019 at 20:33, Matthew Pava wrote:
> It was a little difficult to follow your message because the formatting is
> non-standard, but I think this might be what you’re looking for.
>
> Also, you should try to follow more Python coding conventions: models
> start with an upper case letter. Variables start with a lower case letter.
>
>
>
> And you probably want to use a QuerySet Manager on Customer. Maybe a query
> like this:
>
> Customer.objects.annotate(is_admitted=Case(When(admission_set__discharged=False,
> then=True), default=False).distinct()
>
>
>
>
>
> *From:* django-users@googlegroups.com [mailto:
> django-users@googlegroups.com] *On Behalf Of *Joel Mathew
> *Sent:* Tuesday, April 30, 2019 9:22 AM
> *To:* django-users@googlegroups.com
> *Subject:* Simplifying code with multiple loops and logic, into queryset
> aggregates
>
>
>
> My models:
>
>
>
> class customer(models.Model):
>
> cstid = models.AutoField(primary_key=True, unique=True)
>
> insurance_number = models.CharField(max_length=100, blank=True,
> null=True)
>
> name = models.CharField(max_length=35)
>
> ageyrs = models.IntegerField(blank=True)
>
>
>
> class Admission(models.Model):
>
> id = models.AutoField(primary_key=True, unique=True)
>
> clinic = models.ForeignKey(Clinic, on_delete=models.CASCADE)
>
> customer = models.ForeignKey(customer, on_delete=models.CASCADE)
>
> diagnosis = models.CharField(max_length=2000, default='', blank=
> True)
>
> date_admission = models.DateTimeField(default=timezone.now)
>
> ward = models.ForeignKey(Ward, on_delete=models.CASCADE)
>
> bed = models.ForeignKey(Bed, on_delete=models.CASCADE)
>
> discharged = models.BooleanField(default=False)
>
> ip_number = models.IntegerField(blank=True)
>
> ip_prefix = models.CharField(max_length=20, default='', blank=True
> )
>
>
>
> My objective: Set a variable to a query filter, adding a property,
> 'is_admitted' to the queryset, so that I can pass this query set to the
> template and use the property while displaying data.
>
>
>
> Code:
>
>
>
> def is_admitted(cust):
>
> admission = Admission.objects.filter(customer=cust, discharged=
> False)
>
> admission_results = len(admission)
>
> if admission_results > 0:
>
> return True
>
> return False
>
>
>
> my_q = or_q_if_truthfull(
>
> cstid=HospitalID,
>
> name__lower__contains=name.lower() if name else None,
>
> ageyrs=ageyrs if ageyrs.isdigit() else None,
>
> agemnths=agemnths if agemnths.isdigit() else None,
>
> mobile__contains=mobile if mobile else None,
>
> alternate__contains=alternate if alternate else None,
>
> email__lower__contains=email.lower() if email else None,
>
> address__lower__contains=address.lower() if address else None,
>
> city__lower__contains=city.lower() if city else None
>
> )
>
> ORSearchResult = customer.objects.filter(my_q, linkedclinic=clinicobj)
>
> cust_set = []
>
> cust_admission_status = []
>
> for cust in ORSearchResult:
>
> cust_set.append(cust)
>
> cust_admission_status.append(is_admitted(cust))
>
> print(f"Customer name: {cust.name} Admission status: {
> is_admitted(cust)}")
>
> cust_templ_set = zip(cust_set, cust_admission_status)
>
>
>
> And in template, I will do:
>
>
>
> {% for cust, status in cust_templ_set %}
>
> {{ cust.name }} {{ status }}
>
> {% endfor %}
>
>
>
> I want to understand how I can convert my above code by generating an
> aggregate over the queryset, so that I can use a property of the query,
> and change the template code to the following, and avoid the loop in the
> view, and the zip. So that the template code becomes:
>
>
>
> {% for cust in customers %}
>
> {{ cust.name }} {{ cust.status }}
>
> {% endfor %}
>
>
>
> I am not sure whether I am making complete sense, and can explain further.
>
> Sincerely yours,
>
> Joel G Mathew
>
>
>
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