Updated to Django3

hardware/models.py

@@ -50,7 +50,7 @@ class Item(models.Model):
     """Represents a real world object identified by label"""
 
     # Hardware model/type
-    item_type = models.ForeignKey(ItemType)
+    item_type = models.ForeignKey(ItemType, on_delete=models.CASCADE)
     # Identifies a real world object
     label = models.CharField(max_length=20, unique=True)
     # Is the item available?
@@ -85,17 +85,18 @@ class Borrowing(models.Model):
     """
     objects = BorrowingQuerySet.as_manager()
 
-    user = models.ForeignKey(User)
-    item = models.ForeignKey(Item)
+    user = models.ForeignKey(User, on_delete=models.DO_NOTHING)
+    item = models.ForeignKey(Item, on_delete=models.DO_NOTHING)
     # Instant of creation
     picked_up_time = models.DateTimeField(auto_now_add=True)
     # If null: item has not been returned yet
     return_time = models.DateTimeField(null=True, blank=True)
 
     # Borrowing handled by
-    borrowing_by = models.ForeignKey(User, related_name='hardware_admin_borrowing')
+    borrowing_by = models.ForeignKey(User, related_name='hardware_admin_borrowing', on_delete=models.DO_NOTHING)
     # Return handled by (null until returned)
-    return_by = models.ForeignKey(User, related_name='hardware_admin_return', null=True, blank=True)
+    return_by = models.ForeignKey(User, related_name='hardware_admin_return', null=True, blank=True,
+                                  on_delete=models.SET_NULL)
 
     def get_picked_up_time_ago(self):
         return str(timezone.now() - self.picked_up_time)
@@ -144,11 +145,11 @@ class Request(models.Model):
     objects = RequestQuerySet.as_manager()
 
     # Requested item type
-    item_type = models.ForeignKey(ItemType)
+    item_type = models.ForeignKey(ItemType, on_delete=models.CASCADE)
     # Hacker that made the request
-    user = models.ForeignKey(User)
+    user = models.ForeignKey(User, on_delete=models.CASCADE)
     # Borrowing derived from this request
-    borrowing = models.ForeignKey(Borrowing, null=True, blank=True)
+    borrowing = models.ForeignKey(Borrowing, null=True, blank=True, on_delete=models.CASCADE)
     # Instant of creation
     request_time = models.DateTimeField(auto_now_add=True)