访问 Django 中的外键字段

Question

This is my models.py file:

class Appointment(models.Model):                  
    time = models.TimeField(auto_now_add=False, auto_now=False, null=True, blank=True)
    date = models.DateField(auto_now_add=False, auto_now=False, blank=True, null=True)
    employees = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
    location = models.CharField(max_length=100, blank=True, null=True)

    def __str__(self):
        return self.location

class Patient(models.Model):
    first_name = models.CharField(max_length=60, null=True)
    last_name = models.CharField(max_length=60, null=True)
    appointments = models.ForeignKey(Appointment, on_delete=models.CASCADE)

    def __str__(self):
        return self.first_name

In views.py I am trying to access the first_name of a Patient object, based on Appointment . So, for example, let's say that I have an appointment with a known id , and I want to get the first_name of the patient who has that appointment.

How would I do this in Django? I know only how to access a patient's appointment, but I can't figure out how to access an appointment's patient.

Answer 1

According to your Model design a Appointment has many Patient . Basically what you can do to access a Appointment's Patients is add _set suffix on the reverse relation like following

appointment.patient_set.all()

See the first example here .

Answer 2

Filter patients with the known appointment id. Do something like this in your views.

appointment = get_object_or_404(Appointment, pk = appointment_id)   
patient = Patient.objects.filter(appointments=appointment)

Answer 3

patient__first_name

for condition also you can use for example:

Q(patient__first_name__icontains='John')

note that patient is lowercase