CODEWITHSUNDEEP
pythondjango
Joel G Mathew
Joel G Mathew

Reputation: 8061

How to aggregate, that is to get querysets based on a property of a query

My model:

class ClinicPermissions(models.Model):
    id = models.AutoField(primary_key=True, unique=True)
    clinicid = models.ForeignKey(Clinic, on_delete=models.CASCADE)
    doctorid = models.ForeignKey(doctor, on_delete=models.CASCADE)
    viewperm_choices = (
        (0, 'Cannot view clinic details'),
        (1, 'Can view clinic details')
    )
    viewperms = models.IntegerField(
        choices=viewperm_choices, default=0)
    editperms_choices = (
        (0, 'Cannot edit clinic details'),
        (1, 'Can edit clinic details')
    )
    editperms = models.IntegerField(
        choices=editperms_choices, default=0)
    editdocs_choices = (
        (0, 'Cannot edit doctor details'),
        (1, 'Can edit doctor details')
    )
    editdocs = models.IntegerField(
        choices=editdocs_choices, default=0)

    class Meta:
        unique_together = ["clinicid", "doctorid"]

The above model describes permissions of each doctor in a clinic. I need to get a list of doctor objects associated with a Clinic object, which is stored in ClinicPermissions model, as a queryset and pass it to a form.

i.e

I want to get a specific Clinic.

cl = Clinic.objects.get(id=10)

Then, I want to get a queryset of doctors from the ClinicPermissions, where clinicid = cl:

i.e Something more elegant than the following:

perms = ClinicPermissions.objects.filter(clinicid = cl)
docs = []
for perm in perms:
    docs.append(perm.doctorid)
return docs

Here, docs is a list, but I need a queryset, to pass to a form.

Upvotes: 0

Views: 39

Answers (1)

JPG
JPG

Reputation: 88509

Simply

Doctor.objects.filter(clinicpermissions__clinicid_id=10)

Here the value 10 is the PK of Clinic object

Reference

As a side note, In Django, we will not use id as a suffix to the fields since Django internally handling the same. Similarly, Django handled the Primary field too, hence, no need to define the PK explicitly.

class ClinicPermissions(models.Model):
    id = models.AutoField(primary_key=True, unique=True)
    clinic = models.ForeignKey(Clinic, on_delete=models.CASCADE)
    doctor = models.ForeignKey(Musician, on_delete=models.CASCADE)
    # rest of the fields

Upvotes: 4

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