from django.db import models
class TransportRouteManager(models.Manager):
def get_by_natural_key(self, name):
return self.get(name=name)
[docs]
class TransportRoute(models.Model):
objects = TransportRouteManager()
distance = models.FloatField()
name = models.CharField(max_length=255)
name_de = models.CharField(max_length=255, null=True)
name_en = models.CharField(max_length=255, null=True)
emission_factor = models.ForeignKey("EmissionFactor", on_delete=models.SET_NULL, null=True)
unit = models.ForeignKey("Unit", on_delete=models.SET_NULL, null=True)
[docs]
def natural_key(self):
return (self.name,)
def __str__(self):
result = f"{self.name} ({self.distance} {self.unit}) - {self.emission_factor}"
return result