Django REST framework: Join tables - django

Question

I am trying to make an API view where the user inputs the name of a controller and receives the measurements it can return as a JSON.
models.py
class Microcontrollers(models.Model):
name = models.CharField(max_length=25)
serial_number = models.CharField(max_length=20, blank=True, null=True)
type = models.CharField(max_length=15, blank=True, null=True)
software = models.CharField(max_length=20, blank=True, null=True)
version = models.CharField(max_length=5, blank=True, null=True)
date_installed = models.DateField(blank=True, null=True)
date_battery_last_replaced = models.DateField(blank=True, null=True)
source = models.CharField(max_length=10, blank=True, null=True)
friendly_name = models.CharField(max_length=45, blank=True, null=True)
class MicrocontrollersMeasurements(models.Model):
microcontroller = models.ForeignKey(Microcontrollers, models.DO_NOTHING, blank=True, null=True)
measurement = models.ForeignKey(Measurements, models.DO_NOTHING, blank=True, null=True)
class Measurements(models.Model):
code = models.CharField(max_length=25)
measurement = models.CharField(max_length=25)
unit = models.CharField(max_length=25)
type = models.CharField(max_length=25)
serializers.py
class SourceStationsSerializer(serializers.ModelSerializer):
def create(self, validated_data):
pass
def update(self, instance, validated_data):
pass
class Meta:
model = Microcontrollers
fields = ['id', 'name']
class StationMeasurementsSerializer(serializers.ModelSerializer):
def create(self, validated_data):
pass
def update(self, instance, validated_data):
pass
class Meta:
model = MicrocontrollersMeasurements
fields = '__all__'
class MeasurementsSerializer(serializers.ModelSerializer):
station = SourceStationsSerializer()
stationMeasurements = StationMeasurementsSerializer()
def create(self, validated_data):
pass
def update(self, instance, validated_data):
pass
class Meta:
model = Measurements
fields = '__all__'
The database creates IDs for each controller and measurement. My question is how can i join the 3 tables so i can find the measurements that belong to each controller.

Answer 1

well you dont actually need the intermediate models in django..
class Measurements(models.Model):
microcontroller = models.ForeignKey(Microcontrollers,related_name="measurements",on_delete=models.DO_NOTHING, blank=True, null=True)
code = models.CharField(max_length=25)
measurement = models.CharField(max_length=25)
unit = models.CharField(max_length=25)
type = models.CharField(max_length=25)
note the related_name='measurements"
Now Say,
pic = Microcontrollers.objects.get(id=1) #or any instance of MMicrocontrollers()
measurements_pic = pic.measurements.all() # will get a list of all measurements associated with pic
this "measurements" in pic.measurements.all() here is the related name. Django created the intemediate table and all that stuff.. and simplifies it.
For the output purposes
out = MeasurementsSerializer(measurements_pic,many=True)
will do the job.
Note: 'type' is a keyword in python