1 files changed, 12 insertions, 5 deletions
diff --git a/servo/models/purchases.py b/servo/models/purchases.py
index 015e12c..f79bc6e 100644
--- a/servo/models/purchases.py
+++ b/servo/models/purchases.py
@@ -27,9 +27,10 @@ class PurchaseOrder(models.Model):
     location = models.ForeignKey(
         Location,
         editable=False,
+        on_delete=models.SET_NULL,
         help_text=_('The location from which this PO was created')
     )
-    sales_order = models.ForeignKey(Order, null=True, editable=False)
+    sales_order = models.ForeignKey(Order, null=True, editable=False, on_delete=models.SET_NULL)
     reference = models.CharField(
         blank=True,
         default='',
@@ -43,7 +44,9 @@ class PurchaseOrder(models.Model):
         verbose_name=_("Confirmation"),
     )
 
-    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, editable=False)
+    created_by = models.ForeignKey(settings.AUTH_USER_MODEL,
+        editable=False,
+        on_delete=models.SET_NULL)
     created_at = models.DateTimeField(auto_now_add=True, editable=False)
     submitted_at = models.DateTimeField(null=True, editable=False)
 
@@ -189,7 +192,7 @@ class PurchaseOrder(models.Model):
 
 class PurchaseOrderItem(AbstractOrderItem):
     """
-    An item being purchased
+    A line item on a Purchase Order
     """
     price = models.DecimalField(
         max_digits=8,
@@ -201,6 +204,7 @@ class PurchaseOrderItem(AbstractOrderItem):
     purchase_order = models.ForeignKey(
         PurchaseOrder,
         editable=False,
+        on_delete=models.CASCADE,
         verbose_name=_("Purchase Order")
     )
 
@@ -209,6 +213,7 @@ class PurchaseOrderItem(AbstractOrderItem):
         Order,
         null=True,
         editable=False,
+        on_delete=models.SET_NULL,
     )
 
     sales_order_ref = models.CharField(
@@ -230,7 +235,8 @@ class PurchaseOrderItem(AbstractOrderItem):
     )
     # /end optimization
 
-    order_item = models.ForeignKey(ServiceOrderItem, null=True, editable=False)
+    order_item = models.ForeignKey(ServiceOrderItem,
+        null=True, editable=False, on_delete=models.SET_NULL)
     reference  = models.CharField(default='', blank=True, max_length=128)
     ordered_at = models.DateTimeField(null=True, editable=False)
 
@@ -246,7 +252,8 @@ class PurchaseOrderItem(AbstractOrderItem):
         settings.AUTH_USER_MODEL,
         null=True,
         editable=False,
-        related_name='+'
+        related_name='+',
+        on_delete=models.SET_NULL,
     )
 
     @classmethod