diff --git a/rattail/batch/custorder.py b/rattail/batch/custorder.py
index 5a11273209bed290b1c5b804f5e3b764a099dc7a..947508ad5f64a57688d623136e52014a7757eb39 100644
--- a/rattail/batch/custorder.py
+++ b/rattail/batch/custorder.py
@@ -50,7 +50,12 @@ class CustomerOrderBatchHandler(BatchHandler):
     has_custom_product_autocomplete = False
 
     def get_case_size_for_product(self, product):
-        return product.case_size
+        if product.case_size:
+            return product.case_size
+
+        cost = product.cost
+        if cost:
+            return cost.case_size
 
     def custom_product_autocomplete(self, session, term, **kwargs):
         """
diff --git a/rattail/db/model/custorders.py b/rattail/db/model/custorders.py
index 9eb7a581987c5eb74105303da3daf872002be2b7..3e414ad88ab519af9e251b092152b31d33192dec 100644
--- a/rattail/db/model/custorders.py
+++ b/rattail/db/model/custorders.py
@@ -136,10 +136,14 @@ class CustomerOrder(CustomerOrderBase, Base):
 
     status_code = sa.Column(sa.Integer(), nullable=False)
 
-    items = orm.relationship('CustomerOrderItem', back_populates='order',
-                             collection_class=ordering_list('sequence', count_from=1), doc="""
-    Sequence of :class:`CustomerOrderItem` instances which belong to the order.
-    """)
+    items = orm.relationship(
+        'CustomerOrderItem',
+        back_populates='order',
+        collection_class=ordering_list('sequence', count_from=1),
+        cascade='all, delete-orphan',
+        doc="""
+        Sequence of :class:`CustomerOrderItem` instances which belong to the order.
+        """)
 
     def __str__(self):
         if self.id: