rework main models

dbapp/mapsapp/models.py

@@ -1,15 +1,27 @@
 from django.db import models
 from mainapp.models import Satellite, Polarization, get_default_polarization
+from django.db.models import F, ExpressionWrapper
+from django.db.models.functions import Abs
 
 class Transponders(models.Model):
     name = models.CharField(max_length=30, null=True, blank=True, verbose_name="Название транспондера")
-    frequency = models.FloatField(blank=True, null=True, verbose_name="Центральная частота")
-    frequency_range = models.FloatField(blank=True, null=True, verbose_name="Полоса частот")
-    zone_name = models.CharField(max_length=60, blank=True, null=True, verbose_name="Название зоны")
+    downlink = models.FloatField(blank=True, null=True, verbose_name="Downlink")
+    frequency_range = models.FloatField(blank=True, null=True, verbose_name="Полоса")
+    uplink = models.FloatField(blank=True, null=True, verbose_name="Uplink")
+    zone_name = models.CharField(max_length=255, blank=True, null=True, verbose_name="Название зоны")
     polarization = models.ForeignKey(
         Polarization, default=get_default_polarization, on_delete=models.SET_DEFAULT, related_name="tran_polarizations", null=True, blank=True, verbose_name="Поляризация"
     )
     sat_id = models.ForeignKey(Satellite, on_delete=models.PROTECT, related_name="tran_satellite", verbose_name="Спутник")
+    transfer =models.GeneratedField(
+        expression=ExpressionWrapper(
+            Abs(F('downlink') - F('uplink')),
+            output_field=models.FloatField()
+        ),
+        output_field=models.FloatField(),
+        db_persist=True,
+        null=True, blank=True, verbose_name="Перенос"
+    )
 
     def __str__(self):
         return self.name