How to serialize nested objects with related models? - json

Question

i am really new to DRM and i have to following problem
I have three related models. Now i want to for each sensor values to the related patient. My models look like:
class Sensor(models.Model):
sensor_name = models.CharField(max_length=200, primary_key=True)
sensor_refreshRate = models.FloatField()
sensor_prio = models.IntegerField(choices=[
(1, 1), (2, 2), (3, 3), (4, 4), ], default='1')
sensor_typ = models.CharField(
max_length=200,
choices=[
('bar', 'bar'), ('pie', 'pie'),
('line', 'line'), ('text', 'text'),
],
default='bar'
)
class Patient(models.Model):
firstName = models.CharField(max_length=200)
lastName = models.CharField(max_length=200)
age = models.IntegerField()
doctor = models.ForeignKey(
settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
sensor = models.ManyToManyField(Sensor)
class Value(models.Model):
value_date = models.DateTimeField(auto_now_add=True)
value = models.FloatField()
sensor = models.ForeignKey(Sensor, on_delete=models.CASCADE)
Now i would like to send a JSON file which looks like:
[
{
"value": 445.0,
"sensor": "Pressure",
"patient": 3
},
{
"value": 478.0,
"sensor": "Temperature",
"patient": 3
}
]
Now i am not sure how to serialize my JSON.
Thanks in advance

Answer 1

your data models seems incomplete.
There's no link between the Value model and the Patient one.
So first I'd suggest to modify the Value model
class Value(models.Model):
value_date = models.DateTimeField(auto_now_add=True)
value = models.FloatField()
sensor = models.ForeignKey(Sensor, on_delete=models.CASCADE)
patient = models.ForeignKey(Patient, on_delete=models.CASCADE)
then you could create a queryset
qs = Value.objects.filter(.....).values(
'patient_id', 'sensor__sensor_name', 'value'
)
and the write your serializer